
/* This module contains the external function pcre_compile(), along with
supporting internal functions that are not used by other modules. */

#include "PikaObj.h"
#include "re_config.h"
#define NLBLOCK cd            /* Block containing newline information */
#define PSSTART start_pattern /* Field containing processed string start */
#define PSEND end_pattern     /* Field containing processed string end */

#include "pcre_internal.h"

/* When DEBUG is defined, we need the pcre_printint() function, which is also
used by pcretest. DEBUG is not defined when building a production library. */

#ifdef DEBUG
#include "pcre_printint.src"
#endif

/* Macro for setting individual bits in class bitmaps. */

#define SETBIT(a, b) a[b / 8] |= (1 << (b % 8))

/* Maximum length value to check against when making sure that the integer that
holds the compiled pattern length does not overflow. We make it a bit less than
INT_MAX to allow for adding in group terminating bytes, so that we don't have
to check them every time. */

#define OFLOW_MAX (INT_MAX - 20)

/*************************************************
 *      Code parameters and static tables         *
 *************************************************/

/* This value specifies the size of stack workspace that is used during the
first pre-compile phase that determines how much memory is required. The regex
is partly compiled into this space, but the compiled parts are discarded as
soon as they can be, so that hopefully there will never be an overrun. The code
does, however, check for an overrun. The largest amount I've seen used is 218,
so this number is very generous.

The same workspace is used during the second, actual compile phase for
remembering forward references to groups so that they can be filled in at the
end. Each entry in this list occupies LINK_SIZE bytes, so even when LINK_SIZE
is 4 there is plenty of room. */

#define COMPILE_WORK_SIZE (4096)

/* Table for handling escaped characters in the range '0'-'z'. Positive returns
are simple data values; negative values are for special things like \d and so
on. Zero means further processing is needed (for things like \x), or the escape
is invalid. */

#ifndef EBCDIC /* This is the "normal" table for ASCII systems */
static const short int escapes[] = {
    0,      0,      0,      0,      0,       0,      0,      0,      /* 0 - 7 */
    0,      0,      ':',    ';',    '<',     '=',    '>',    '?',    /* 8 - ? */
    '@',    -ESC_A, -ESC_B, -ESC_C, -ESC_D,  -ESC_E, 0,      -ESC_G, /* @ - G */
    -ESC_H, 0,      0,      -ESC_K, 0,       0,      0,      0,      /* H - O */
    -ESC_P, -ESC_Q, -ESC_R, -ESC_S, 0,       0,      -ESC_V, -ESC_W, /* P - W */
    -ESC_X, 0,      -ESC_Z, '[',    '\\',    ']',    '^',    '_',    /* X - _ */
    '`',    7,      -ESC_b, 0,      -ESC_d,  ESC_e,  ESC_f,  0,      /* ` - g */
    -ESC_h, 0,      0,      -ESC_k, 0,       0,      ESC_n,  0,      /* h - o */
    -ESC_p, 0,      ESC_r,  -ESC_s, ESC_tee, 0,      -ESC_v, -ESC_w, /* p - w */
    0,      0,      -ESC_z                                           /* x - z */
};

#else /* This is the "abnormal" table for EBCDIC systems */
static const short int escapes[] = {
    /*  48 */ 0,
    0,
    0,
    '.',
    '<',
    '(',
    '+',
    '|',
    /*  50 */ '&',
    0,
    0,
    0,
    0,
    0,
    0,
    0,
    /*  58 */ 0,
    0,
    '!',
    '$',
    '*',
    ')',
    ';',
    '~',
    /*  60 */ '-',
    '/',
    0,
    0,
    0,
    0,
    0,
    0,
    /*  68 */ 0,
    0,
    '|',
    ',',
    '%',
    '_',
    '>',
    '?',
    /*  70 */ 0,
    0,
    0,
    0,
    0,
    0,
    0,
    0,
    /*  78 */ 0,
    '`',
    ':',
    '#',
    '@',
    '\'',
    '=',
    '"',
    /*  80 */ 0,
    7,
    -ESC_b,
    0,
    -ESC_d,
    ESC_e,
    ESC_f,
    0,
    /*  88 */ -ESC_h,
    0,
    0,
    '{',
    0,
    0,
    0,
    0,
    /*  90 */ 0,
    0,
    -ESC_k,
    'l',
    0,
    ESC_n,
    0,
    -ESC_p,
    /*  98 */ 0,
    ESC_r,
    0,
    '}',
    0,
    0,
    0,
    0,
    /*  A0 */ 0,
    '~',
    -ESC_s,
    ESC_tee,
    0,
    -ESC_v,
    -ESC_w,
    0,
    /*  A8 */ 0,
    -ESC_z,
    0,
    0,
    0,
    '[',
    0,
    0,
    /*  B0 */ 0,
    0,
    0,
    0,
    0,
    0,
    0,
    0,
    /*  B8 */ 0,
    0,
    0,
    0,
    0,
    ']',
    '=',
    '-',
    /*  C0 */ '{',
    -ESC_A,
    -ESC_B,
    -ESC_C,
    -ESC_D,
    -ESC_E,
    0,
    -ESC_G,
    /*  C8 */ -ESC_H,
    0,
    0,
    0,
    0,
    0,
    0,
    0,
    /*  D0 */ '}',
    0,
    -ESC_K,
    0,
    0,
    0,
    0,
    -ESC_P,
    /*  D8 */ -ESC_Q,
    -ESC_R,
    0,
    0,
    0,
    0,
    0,
    0,
    /*  E0 */ '\\',
    0,
    -ESC_S,
    0,
    0,
    -ESC_V,
    -ESC_W,
    -ESC_X,
    /*  E8 */ 0,
    -ESC_Z,
    0,
    0,
    0,
    0,
    0,
    0,
    /*  F0 */ 0,
    0,
    0,
    0,
    0,
    0,
    0,
    0,
    /*  F8 */ 0,
    0,
    0,
    0,
    0,
    0,
    0,
    0};
#endif

/* Table of special "verbs" like (*PRUNE). This is a short table, so it is
searched linearly. Put all the names into a single string, in order to reduce
the number of relocations when a shared library is dynamically linked. */

typedef struct verbitem {
    int len;
    int op;
} verbitem;

static const char verbnames[] =
    "ACCEPT\0"
    "COMMIT\0"
    "F\0"
    "FAIL\0"
    "PRUNE\0"
    "SKIP\0"
    "THEN";

static verbitem verbs[] = {{6, OP_ACCEPT}, {6, OP_COMMIT}, {1, OP_FAIL},
                           {4, OP_FAIL},   {5, OP_PRUNE},  {4, OP_SKIP},
                           {4, OP_THEN}};

static int verbcount = sizeof(verbs) / sizeof(verbitem);

/* Tables of names of POSIX character classes and their lengths. The names are
now all in a single string, to reduce the number of relocations when a shared
library is dynamically loaded. The list of lengths is terminated by a zero
length entry. The first three must be alpha, lower, upper, as this is assumed
for handling case independence. */

static const char posix_names[] =
    "alpha\0"
    "lower\0"
    "upper\0"
    "alnum\0"
    "ascii\0"
    "blank\0"
    "cntrl\0"
    "digit\0"
    "graph\0"
    "print\0"
    "punct\0"
    "space\0"
    "word\0"
    "xdigit";

static const uschar posix_name_lengths[] = {5, 5, 5, 5, 5, 5, 5, 5,
                                            5, 5, 5, 5, 4, 6, 0};

/* Table of class bit maps for each POSIX class. Each class is formed from a
base map, with an optional addition or removal of another map. Then, for some
classes, there is some additional tweaking: for [:blank:] the vertical space
characters are removed, and for [:alpha:] and [:alnum:] the underscore
character is removed. The triples in the table consist of the base map offset,
second map offset or -1 if no second map, and a non-negative value for map
addition or a negative value for map subtraction (if there are two maps). The
absolute value of the third field has these meanings: 0 => no tweaking, 1 =>
remove vertical space characters, 2 => remove underscore. */

static const int posix_class_maps[] = {
    cbit_word,   cbit_digit, -2, /* alpha */
    cbit_lower,  -1,         0,  /* lower */
    cbit_upper,  -1,         0,  /* upper */
    cbit_word,   -1,         2,  /* alnum - word without underscore */
    cbit_print,  cbit_cntrl, 0,  /* ascii */
    cbit_space,  -1,         1,  /* blank - a GNU extension */
    cbit_cntrl,  -1,         0,  /* cntrl */
    cbit_digit,  -1,         0,  /* digit */
    cbit_graph,  -1,         0,  /* graph */
    cbit_print,  -1,         0,  /* print */
    cbit_punct,  -1,         0,  /* punct */
    cbit_space,  -1,         0,  /* space */
    cbit_word,   -1,         0,  /* word - a Perl extension */
    cbit_xdigit, -1,         0   /* xdigit */
};

#define STRING(a) #a
#define XSTRING(s) STRING(s)

/* The texts of compile-time error messages. These are "char *" because they
are passed to the outside world. Do not ever re-use any error number, because
they are documented. Always add a new error instead. Messages marked DEAD below
are no longer used. This used to be a table of strings, but in order to reduce
the number of relocations needed when a shared library is loaded dynamically,
it is now one long string. We cannot use a table of offsets, because the
lengths of inserts such as XSTRING(MAX_NAME_SIZE) are not known. Instead, we
simply count through to the one we want - this isn't a performance issue
because these strings are used only when there is a compilation error. */

static const char error_texts[] =
  "no error\0"
  "\\ at end of pattern\0"
  "\\c at end of pattern\0"
  "unrecognized character follows \\\0"
  "numbers out of order in {} quantifier\0"
  /* 5 */
  "number too big in {} quantifier\0"
  "missing terminating ] for character class\0"
  "invalid escape sequence in character class\0"
  "range out of order in character class\0"
  "nothing to repeat\0"
  /* 10 */
  "operand of unlimited repeat could match the empty string\0"  /** DEAD **/
  "internal error: unexpected repeat\0"
  "unrecognized character after (? or (?-\0"
  "POSIX named classes are supported only within a class\0"
  "missing )\0"
  /* 15 */
  "reference to non-existent subpattern\0"
  "erroffset passed as NULL\0"
  "unknown option bit(s) set\0"
  "missing ) after comment\0"
  "parentheses nested too deeply\0"  /** DEAD **/
  /* 20 */
  "regular expression is too large\0"
  "failed to get memory\0"
  "unmatched parentheses\0"
  "internal error: code overflow\0"
  "unrecognized character after (?<\0"
  /* 25 */
  "lookbehind assertion is not fixed length\0"
  "malformed number or name after (?(\0"
  "conditional group contains more than two branches\0"
  "assertion expected after (?(\0"
  "(?R or (?[+-]digits must be followed by )\0"
  /* 30 */
  "unknown POSIX class name\0"
  "POSIX collating elements are not supported\0"
  "this version of PCRE is not compiled with PCRE_UTF8 support\0"
  "spare error\0"  /** DEAD **/
  "character value in \\x{...} sequence is too large\0"
  /* 35 */
  "invalid condition (?(0)\0"
  "\\C not allowed in lookbehind assertion\0"
  "PCRE does not support \\L, \\l, \\N, \\U, or \\u\0"
  "number after (?C is > 255\0"
  "closing ) for (?C expected\0"
  /* 40 */
  "recursive call could loop indefinitely\0"
  "unrecognized character after (?P\0"
  "syntax error in subpattern name (missing terminator)\0"
  "two named subpatterns have the same name\0"
  "invalid UTF-8 string\0"
  /* 45 */
  "support for \\P, \\p, and \\X has not been compiled\0"
  "malformed \\P or \\p sequence\0"
  "unknown property name after \\P or \\p\0"
  "subpattern name is too long (maximum " XSTRING(MAX_NAME_SIZE) " characters)\0"
  "too many named subpatterns (maximum " XSTRING(MAX_NAME_COUNT) ")\0"
  /* 50 */
  "repeated subpattern is too long\0"    /** DEAD **/
  "octal value is greater than \\377 (not in UTF-8 mode)\0"
  "internal error: overran compiling workspace\0"
  "internal error: previously-checked referenced subpattern not found\0"
  "DEFINE group contains more than one branch\0"
  /* 55 */
  "repeating a DEFINE group is not allowed\0"
  "inconsistent NEWLINE options\0"
  "\\g is not followed by a braced name or an optionally braced non-zero number\0"
  "(?+ or (?- or (?(+ or (?(- must be followed by a non-zero number\0"
  "(*VERB) with an argument is not supported\0"
  /* 60 */
  "(*VERB) not recognized\0"
  "number is too big\0"
  "subpattern name expected\0"
  "digit expected after (?+";

/* Table to identify digits and hex digits. This is used when compiling
patterns. Note that the tables in chartables are dependent on the locale, and
may mark arbitrary characters as digits - but the PCRE compiling code expects
to handle only 0-9, a-z, and A-Z as digits when compiling. That is why we have
a private table here. It costs 256 bytes, but it is a lot faster than doing
character value tests (at least in some simple cases I timed), and in some
applications one wants PCRE to compile efficiently as well as match
efficiently.

For convenience, we use the same bit definitions as in chartables:

  0x04   decimal digit
  0x08   hexadecimal digit

Then we can use ctype_digit and ctype_xdigit in the code. */

#ifndef EBCDIC /* This is the "normal" case, for ASCII systems */
static const unsigned char digitab[] = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*   0-  7 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*   8- 15 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  16- 23 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  24- 31 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*    - '  */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  ( - /  */
    0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,  /*  0 - 7  */
    0x0c, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  8 - ?  */
    0x00, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x00,  /*  @ - G  */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  H - O  */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  P - W  */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  X - _  */
    0x00, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x00,  /*  ` - g  */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  h - o  */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  p - w  */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  x -127 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 128-135 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 136-143 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 144-151 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 152-159 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 160-167 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 168-175 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 176-183 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 184-191 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 192-199 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 200-207 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 208-215 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 216-223 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 224-231 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 232-239 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 240-247 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; /* 248-255 */

#else /* This is the "abnormal" case, for EBCDIC systems */
static const unsigned char digitab[] = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*   0-  7  0 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*   8- 15    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  16- 23 10 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  24- 31    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  32- 39 20 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  40- 47    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  48- 55 30 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  56- 63    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*    - 71 40 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  72- |     */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  & - 87 50 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  88- 95    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  - -103 60 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 104- ?     */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 112-119 70 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 120- "     */
    0x00, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x00,  /* 128- g  80 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  h -143    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 144- p  90 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  q -159    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 160- x  A0 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  y -175    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  ^ -183 B0 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 184-191    */
    0x00, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x00,  /*  { - G  C0 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  H -207    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  } - P  D0 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  Q -223    */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  \ - X  E0 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /*  Y -239    */
    0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,  /*  0 - 7  F0 */
    0x0c, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; /*  8 -255    */

static const unsigned char ebcdic_chartab[] =
    {                                                /* chartable partial dup */
     0x80, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, /*   0-  7 */
     0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x00, 0x00, /*   8- 15 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, /*  16- 23 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  24- 31 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, /*  32- 39 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  40- 47 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  48- 55 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  56- 63 */
     0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*    - 71 */
     0x00, 0x00, 0x00, 0x80, 0x00, 0x80, 0x80, 0x80, /*  72- |  */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  & - 87 */
     0x00, 0x00, 0x00, 0x80, 0x80, 0x80, 0x00, 0x00, /*  88- 95 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  - -103 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x80, /* 104- ?  */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 112-119 */
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 120- "  */
     0x00, 0x1a, 0x1a, 0x1a, 0x1a, 0x1a, 0x1a, 0x12, /* 128- g  */
     0x12, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  h -143 */
     0x00, 0x12, 0x12, 0x12, 0x12, 0x12, 0x12, 0x12, /* 144- p  */
     0x12, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  q -159 */
     0x00, 0x00, 0x12, 0x12, 0x12, 0x12, 0x12, 0x12, /* 160- x  */
     0x12, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  y -175 */
     0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  ^ -183 */
     0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, /* 184-191 */
     0x80, 0x1a, 0x1a, 0x1a, 0x1a, 0x1a, 0x1a, 0x12, /*  { - G  */
     0x12, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  H -207 */
     0x00, 0x12, 0x12, 0x12, 0x12, 0x12, 0x12, 0x12, /*  } - P  */
     0x12, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  Q -223 */
     0x00, 0x00, 0x12, 0x12, 0x12, 0x12, 0x12, 0x12, /*  \ - X  */
     0x12, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*  Y -239 */
     0x1c, 0x1c, 0x1c, 0x1c, 0x1c, 0x1c, 0x1c, 0x1c, /*  0 - 7  */
     0x1c, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; /*  8 -255 */
#endif

/* Definition to allow mutual recursion */

static BOOL compile_regex(int,
                          int,
                          uschar**,
                          const uschar**,
                          int*,
                          BOOL,
                          BOOL,
                          int,
                          int*,
                          int*,
                          branch_chain*,
                          compile_data*,
                          int*);

/*************************************************
 *            Find an error text                  *
 *************************************************/

/* The error texts are now all in one long string, to save on relocations. As
some of the text is of unknown length, we can't use a table of offsets.
Instead, just count through the strings. This is not a performance issue
because it happens only when there has been a compilation error.

Argument:   the error number
Returns:    pointer to the error string
*/

static const char* find_error_text(int n) {
    const char* s = error_texts;
    for (; n > 0; n--)
        while (*s++ != 0)
            ;
    return s;
}

/*************************************************
 *            Handle escapes                      *
 *************************************************/

/* This function is called when a \ has been encountered. It either returns a
positive value for a simple escape such as \n, or a negative value which
encodes one of the more complicated things such as \d. A backreference to group
n is returned as -(ESC_REF + n); ESC_REF is the highest ESC_xxx macro. When
UTF-8 is enabled, a positive value greater than 255 may be returned. On entry,
ptr is pointing at the \. On exit, it is on the final character of the escape
sequence.

Arguments:
  ptrptr         points to the pattern position pointer
  errorcodeptr   points to the errorcode variable
  bracount       number of previous extracting brackets
  options        the options bits
  isclass        TRUE if inside a character class

Returns:         zero or positive => a data character
                 negative => a special escape sequence
                 on error, errorcodeptr is set
*/

static int check_escape(const uschar** ptrptr,
                        int* errorcodeptr,
                        int bracount,
                        int options,
                        BOOL isclass) {
    BOOL utf8 = (options & PCRE_UTF8) != 0;
    const uschar* ptr = *ptrptr + 1;
    int c, i;

    GETCHARINCTEST(c, ptr); /* Get character value, increment pointer */
    ptr--;                  /* Set pointer back to the last byte */

    /* If backslash is at the end of the pattern, it's an error. */

    if (c == 0)
        *errorcodeptr = ERR1;

        /* Non-alphanumerics are literals. For digits or letters, do an initial
        lookup in a table. A non-zero result is something that can be returned
        immediately. Otherwise further processing may be required. */

#ifndef EBCDIC /* ASCII coding */
    else if (c < '0' || c > 'z') {
    } /* Not alphanumeric */
    else if ((i = escapes[c - '0']) != 0)
        c = i;

#else /* EBCDIC coding */
    else if (c < 'a' || (ebcdic_chartab[c] & 0x0E) == 0) {
    } /* Not alphanumeric */
    else if ((i = escapes[c - 0x48]) != 0)
        c = i;
#endif

    /* Escapes that need further processing, or are illegal. */

    else {
        const uschar* oldptr;
        BOOL braced, negated;

        switch (c) {
                /* A number of Perl escapes are not handled by PCRE. We give an
                explicit error. */

            case 'l':
            case 'L':
            case 'N':
            case 'u':
            case 'U':
                *errorcodeptr = ERR37;
                break;

                /* \g must be followed by a number, either plain or braced. If
                positive, it is an absolute backreference. If negative, it is a
                relative backreference. This is a Perl 5.10 feature. Perl 5.10
                also supports \g{name} as a reference to a named group. This is
                part of Perl's movement towards a unified syntax for back
                references. As this is synonymous with \k{name}, we fudge it up
                by pretending it really was \k. */

            case 'g':
                if (ptr[1] == '{') {
                    const uschar* p;
                    for (p = ptr + 2; *p != 0 && *p != '}'; p++)
                        if (*p != '-' && (digitab[*p] & ctype_digit) == 0)
                            break;
                    if (*p != 0 && *p != '}') {
                        c = -ESC_k;
                        break;
                    }
                    braced = TRUE;
                    ptr++;
                } else
                    braced = FALSE;

                if (ptr[1] == '-') {
                    negated = TRUE;
                    ptr++;
                } else
                    negated = FALSE;

                c = 0;
                while ((digitab[ptr[1]] & ctype_digit) != 0)
                    c = c * 10 + *(++ptr) - '0';

                if (c < 0) {
                    *errorcodeptr = ERR61;
                    break;
                }

                if (c == 0 || (braced && *(++ptr) != '}')) {
                    *errorcodeptr = ERR57;
                    break;
                }

                if (negated) {
                    if (c > bracount) {
                        *errorcodeptr = ERR15;
                        break;
                    }
                    c = bracount - (c - 1);
                }

                c = -(ESC_REF + c);
                break;

                /* The handling of escape sequences consisting of a string of
                digits starting with one that is not zero is not
                straightforward. By experiment, the way Perl works seems to be
                as follows:

                Outside a character class, the digits are read as a decimal
                number. If the number is less than 10, or if there are that many
                previous extracting left brackets, then it is a back reference.
                Otherwise, up to three octal digits are read to form an escaped
                byte. Thus \123 is likely to be octal 123 (cf \0123, which is
                octal 012 followed by the literal 3). If the octal value is
                greater than 377, the least significant 8 bits are taken. Inside
                a character class, \ followed by a digit is always an octal
                number. */

            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
            case '8':
            case '9':

                if (!isclass) {
                    oldptr = ptr;
                    c -= '0';
                    while ((digitab[ptr[1]] & ctype_digit) != 0)
                        c = c * 10 + *(++ptr) - '0';
                    if (c < 0) {
                        *errorcodeptr = ERR61;
                        break;
                    }
                    if (c < 10 || c <= bracount) {
                        c = -(ESC_REF + c);
                        break;
                    }
                    ptr = oldptr; /* Put the pointer back and fall through */
                }

                /* Handle an octal number following \. If the first digit is 8
                or 9, Perl generates a binary zero byte and treats the digit as
                a following literal. Thus we have to pull back the pointer by
                one. */

                if ((c = *ptr) >= '8') {
                    ptr--;
                    c = 0;
                    break;
                }

                /* \0 always starts an octal number, but we may drop through to
                here with a larger first octal digit. The original code used
                just to take the least significant 8 bits of octal numbers (I
                think this is what early Perls used to do). Nowadays we allow
                for larger numbers in UTF-8 mode, but no more than 3 octal
                digits. */

            case '0':
                c -= '0';
                while (i++ < 2 && ptr[1] >= '0' && ptr[1] <= '7')
                    c = c * 8 + *(++ptr) - '0';
                if (!utf8 && c > 255)
                    *errorcodeptr = ERR51;
                break;

                /* \x is complicated. \x{ddd} is a character number which can be
                greater than 0xff in utf8 mode, but only if the ddd are hex
                digits. If not, { is treated as a data character. */

            case 'x':
                if (ptr[1] == '{') {
                    const uschar* pt = ptr + 2;
                    int count = 0;

                    c = 0;
                    while ((digitab[*pt] & ctype_xdigit) != 0) {
                        register int cc = *pt++;
                        if (c == 0 && cc == '0')
                            continue; /* Leading zeroes */
                        count++;

#ifndef EBCDIC /* ASCII coding */
                        if (cc >= 'a')
                            cc -= 32; /* Convert to upper case */
                        c = (c << 4) + cc - ((cc < 'A') ? '0' : ('A' - 10));
#else /* EBCDIC coding */
                        if (cc >= 'a' && cc <= 'z')
                            cc += 64; /* Convert to upper case */
                        c = (c << 4) + cc - ((cc >= '0') ? '0' : ('A' - 10));
#endif
                    }

                    if (*pt == '}') {
                        if (c < 0 || count > (utf8 ? 8 : 2))
                            *errorcodeptr = ERR34;
                        ptr = pt;
                        break;
                    }

                    /* If the sequence of hex digits does not end with '}', then
                    we don't recognize this construct; fall through to the
                    normal \x handling. */
                }

                /* Read just a single-byte hex-defined char */

                c = 0;
                while (i++ < 2 && (digitab[ptr[1]] & ctype_xdigit) != 0) {
                    int cc;        /* Some compilers don't like ++ */
                    cc = *(++ptr); /* in initializers */
#ifndef EBCDIC                     /* ASCII coding */
                    if (cc >= 'a')
                        cc -= 32; /* Convert to upper case */
                    c = c * 16 + cc - ((cc < 'A') ? '0' : ('A' - 10));
#else /* EBCDIC coding */
                    if (cc <= 'z')
                        cc += 64; /* Convert to upper case */
                    c = c * 16 + cc - ((cc >= '0') ? '0' : ('A' - 10));
#endif
                }
                break;

                /* For \c, a following letter is upper-cased; then the 0x40 bit
                is flipped. This coding is ASCII-specific, but then the whole
                concept of \cx is ASCII-specific. (However, an EBCDIC equivalent
                has now been added.) */

            case 'c':
                c = *(++ptr);
                if (c == 0) {
                    *errorcodeptr = ERR2;
                    break;
                }

#ifndef EBCDIC /* ASCII coding */
                if (c >= 'a' && c <= 'z')
                    c -= 32;
                c ^= 0x40;
#else /* EBCDIC coding */
                if (c >= 'a' && c <= 'z')
                    c += 64;
                c ^= 0xC0;
#endif
                break;

                /* PCRE_EXTRA enables extensions to Perl in the matter of
                escapes. Any other alphanumeric following \ is an error if
                PCRE_EXTRA was set; otherwise, for Perl compatibility, it is a
                literal. This code looks a bit odd, but there used to be some
                cases other than the default, and there may be again in future,
                so I haven't "optimized" it. */

            default:
                if ((options & PCRE_EXTRA) != 0)
                    switch (c) {
                        default:
                            *errorcodeptr = ERR3;
                            break;
                    }
                break;
        }
    }

    *ptrptr = ptr;
    return c;
}

#ifdef SUPPORT_UCP
/*************************************************
 *               Handle \P and \p                 *
 *************************************************/

/* This function is called after \P or \p has been encountered, provided that
PCRE is compiled with support for Unicode properties. On entry, ptrptr is
pointing at the P or p. On exit, it is pointing at the final character of the
escape sequence.

Argument:
  ptrptr         points to the pattern position pointer
  negptr         points to a boolean that is set TRUE for negation else FALSE
  dptr           points to an int that is set to the detailed property value
  errorcodeptr   points to the error code variable

Returns:         type value from ucp_type_table, or -1 for an invalid type
*/

static int get_ucp(const uschar** ptrptr,
                   BOOL* negptr,
                   int* dptr,
                   int* errorcodeptr) {
    int c, i, bot, top;
    const uschar* ptr = *ptrptr;
    char name[32];

    c = *(++ptr);
    if (c == 0)
        goto ERROR_RETURN;

    *negptr = FALSE;

    /* \P or \p can be followed by a name in {}, optionally preceded by ^ for
    negation. */

    if (c == '{') {
        if (ptr[1] == '^') {
            *negptr = TRUE;
            ptr++;
        }
        for (i = 0; i < (int)sizeof(name) - 1; i++) {
            c = *(++ptr);
            if (c == 0)
                goto ERROR_RETURN;
            if (c == '}')
                break;
            name[i] = c;
        }
        if (c != '}')
            goto ERROR_RETURN;
        name[i] = 0;
    }

    /* Otherwise there is just one following character */

    else {
        name[0] = c;
        name[1] = 0;
    }

    *ptrptr = ptr;

    /* Search for a recognized property name using binary chop */

    bot = 0;
    top = _pcre_utt_size;

    while (bot < top) {
        i = (bot + top) >> 1;
        c = strcmp(name, _pcre_utt_names + _pcre_utt[i].name_offset);
        if (c == 0) {
            *dptr = _pcre_utt[i].value;
            return _pcre_utt[i].type;
        }
        if (c > 0)
            bot = i + 1;
        else
            top = i;
    }

    *errorcodeptr = ERR47;
    *ptrptr = ptr;
    return -1;

ERROR_RETURN:
    *errorcodeptr = ERR46;
    *ptrptr = ptr;
    return -1;
}
#endif

/*************************************************
 *            Check for counted repeat            *
 *************************************************/

/* This function is called when a '{' is encountered in a place where it might
start a quantifier. It looks ahead to see if it really is a quantifier or not.
It is only a quantifier if it is one of the forms {ddd} {ddd,} or {ddd,ddd}
where the ddds are digits.

Arguments:
  p         pointer to the first char after '{'

Returns:    TRUE or FALSE
*/

static BOOL is_counted_repeat(const uschar* p) {
    if ((digitab[*p++] & ctype_digit) == 0)
        return FALSE;
    while ((digitab[*p] & ctype_digit) != 0)
        p++;
    if (*p == '}')
        return TRUE;

    if (*p++ != ',')
        return FALSE;
    if (*p == '}')
        return TRUE;

    if ((digitab[*p++] & ctype_digit) == 0)
        return FALSE;
    while ((digitab[*p] & ctype_digit) != 0)
        p++;

    return (*p == '}');
}

/*************************************************
 *         Read repeat counts                     *
 *************************************************/

/* Read an item of the form {n,m} and return the values. This is called only
after is_counted_repeat() has confirmed that a repeat-count quantifier exists,
so the syntax is guaranteed to be correct, but we need to check the values.

Arguments:
  p              pointer to first char after '{'
  minp           pointer to int for min
  maxp           pointer to int for max
                 returned as -1 if no max
  errorcodeptr   points to error code variable

Returns:         pointer to '}' on success;
                 current ptr on error, with errorcodeptr set non-zero
*/

static const uschar* read_repeat_counts(const uschar* p,
                                        int* minp,
                                        int* maxp,
                                        int* errorcodeptr) {
    int min = 0;
    int max = -1;

    /* Read the minimum value and do a paranoid check: a negative value
    indicates an integer overflow. */

    while ((digitab[*p] & ctype_digit) != 0)
        min = min * 10 + *p++ - '0';
    if (min < 0 || min > 65535) {
        *errorcodeptr = ERR5;
        return p;
    }

    /* Read the maximum value if there is one, and again do a paranoid on its
    size. Also, max must not be less than min. */

    if (*p == '}')
        max = min;
    else {
        if (*(++p) != '}') {
            max = 0;
            while ((digitab[*p] & ctype_digit) != 0)
                max = max * 10 + *p++ - '0';
            if (max < 0 || max > 65535) {
                *errorcodeptr = ERR5;
                return p;
            }
            if (max < min) {
                *errorcodeptr = ERR4;
                return p;
            }
        }
    }

    /* Fill in the required variables, and pass back the pointer to the
    terminating
    '}'. */

    *minp = min;
    *maxp = max;
    return p;
}

/*************************************************
 *       Find forward referenced subpattern       *
 *************************************************/

/* This function scans along a pattern's text looking for capturing
subpatterns, and counting them. If it finds a named pattern that matches the
name it is given, it returns its number. Alternatively, if the name is NULL, it
returns when it reaches a given numbered subpattern. This is used for forward
references to subpatterns. We know that if (?P< is encountered, the name will
be terminated by '>' because that is checked in the first pass.

Arguments:
  ptr          current position in the pattern
  count        current count of capturing parens so far encountered
  name         name to seek, or NULL if seeking a numbered subpattern
  lorn         name length, or subpattern number if name is NULL
  xmode        TRUE if we are in /x mode

Returns:       the number of the named subpattern, or -1 if not found
*/

static int find_parens(const uschar* ptr,
                       int count,
                       const uschar* name,
                       int lorn,
                       BOOL xmode) {
    const uschar* thisname;

    for (; *ptr != 0; ptr++) {
        int term;

        /* Skip over backslashed characters and also entire \Q...\E */

        if (*ptr == '\\') {
            if (*(++ptr) == 0)
                return -1;
            if (*ptr == 'Q')
                for (;;) {
                    while (*(++ptr) != 0 && *ptr != '\\')
                        ;
                    if (*ptr == 0)
                        return -1;
                    if (*(++ptr) == 'E')
                        break;
                }
            continue;
        }

        /* Skip over character classes */

        if (*ptr == '[') {
            while (*(++ptr) != ']') {
                if (*ptr == 0)
                    return -1;
                if (*ptr == '\\') {
                    if (*(++ptr) == 0)
                        return -1;
                    if (*ptr == 'Q')
                        for (;;) {
                            while (*(++ptr) != 0 && *ptr != '\\')
                                ;
                            if (*ptr == 0)
                                return -1;
                            if (*(++ptr) == 'E')
                                break;
                        }
                    continue;
                }
            }
            continue;
        }

        /* Skip comments in /x mode */

        if (xmode && *ptr == '#') {
            while (*(++ptr) != 0 && *ptr != '\n')
                ;
            if (*ptr == 0)
                return -1;
            continue;
        }

        /* An opening parens must now be a real metacharacter */

        if (*ptr != '(')
            continue;
        if (ptr[1] != '?' && ptr[1] != '*') {
            count++;
            if (name == NULL && count == lorn)
                return count;
            continue;
        }

        ptr += 2;
        if (*ptr == 'P')
            ptr++; /* Allow optional P */

        /* We have to disambiguate (?<! and (?<= from (?<name> */

        if ((*ptr != '<' || ptr[1] == '!' || ptr[1] == '=') && *ptr != '\'')
            continue;

        count++;

        if (name == NULL && count == lorn)
            return count;
        term = *ptr++;
        if (term == '<')
            term = '>';
        thisname = ptr;
        while (*ptr != term)
            ptr++;
        if (name != NULL && lorn == ptr - thisname &&
            strncmp((const char*)name, (const char*)thisname, lorn) == 0)
            return count;
    }

    return -1;
}

/*************************************************
 *      Find first significant op code            *
 *************************************************/

/* This is called by several functions that scan a compiled expression looking
for a fixed first character, or an anchoring op code etc. It skips over things
that do not influence this. For some calls, a change of option is important.
For some calls, it makes sense to skip negative forward and all backward
assertions, and also the \b assertion; for others it does not.

Arguments:
  code         pointer to the start of the group
  options      pointer to external options
  optbit       the option bit whose changing is significant, or
                 zero if none are
  skipassert   TRUE if certain assertions are to be skipped

Returns:       pointer to the first significant opcode
*/

static const uschar* first_significant_code(const uschar* code,
                                            int* options,
                                            int optbit,
                                            BOOL skipassert) {
    for (;;) {
        switch ((int)*code) {
            case OP_OPT:
                if (optbit > 0 &&
                    ((int)code[1] & optbit) != (*options & optbit))
                    *options = (int)code[1];
                code += 2;
                break;

            case OP_ASSERT_NOT:
            case OP_ASSERTBACK:
            case OP_ASSERTBACK_NOT:
                if (!skipassert)
                    return code;
                do
                    code += GET(code, 1);
                while (*code == OP_ALT);
                code += _pcre_OP_lengths[*code];
                break;

            case OP_WORD_BOUNDARY:
            case OP_NOT_WORD_BOUNDARY:
                if (!skipassert)
                    return code;
                /* Fall through */

            case OP_CALLOUT:
            case OP_CREF:
            case OP_RREF:
            case OP_DEF:
                code += _pcre_OP_lengths[*code];
                break;

            default:
                return code;
        }
    }
    /* Control never reaches here */
}

/*************************************************
 *        Find the fixed length of a pattern      *
 *************************************************/

/* Scan a pattern and compute the fixed length of subject that will match it,
if the length is fixed. This is needed for dealing with backward assertions.
In UTF8 mode, the result is in characters rather than bytes.

Arguments:
  code     points to the start of the pattern (the bracket)
  options  the compiling options

Returns:   the fixed length, or -1 if there is no fixed length,
             or -2 if \C was encountered
*/

static int find_fixedlength(uschar* code, int options) {
    int length = -1;

    register int branchlength = 0;
    register uschar* cc = code + 1 + LINK_SIZE;

    /* Scan along the opcodes for this branch. If we get to the end of the
    branch, check the length against that of the other branches. */

    for (;;) {
        int d;
        register int op = *cc;
        switch (op) {
            case OP_CBRA:
            case OP_BRA:
            case OP_ONCE:
            case OP_COND:
                d = find_fixedlength(cc + ((op == OP_CBRA) ? 2 : 0), options);
                if (d < 0)
                    return d;
                branchlength += d;
                do
                    cc += GET(cc, 1);
                while (*cc == OP_ALT);
                cc += 1 + LINK_SIZE;
                break;

                /* Reached end of a branch; if it's a ket it is the end of a
                nested call. If it's ALT it is an alternation in a nested call.
                If it is END it's the end of the outer call. All can be handled
                by the same code. */

            case OP_ALT:
            case OP_KET:
            case OP_KETRMAX:
            case OP_KETRMIN:
            case OP_END:
                if (length < 0)
                    length = branchlength;
                else if (length != branchlength)
                    return -1;
                if (*cc != OP_ALT)
                    return length;
                cc += 1 + LINK_SIZE;
                branchlength = 0;
                break;

                /* Skip over assertive subpatterns */

            case OP_ASSERT:
            case OP_ASSERT_NOT:
            case OP_ASSERTBACK:
            case OP_ASSERTBACK_NOT:
                do
                    cc += GET(cc, 1);
                while (*cc == OP_ALT);
                /* Fall through */

                /* Skip over things that don't match chars */

            case OP_REVERSE:
            case OP_CREF:
            case OP_RREF:
            case OP_DEF:
            case OP_OPT:
            case OP_CALLOUT:
            case OP_SOD:
            case OP_SOM:
            case OP_EOD:
            case OP_EODN:
            case OP_CIRC:
            case OP_DOLL:
            case OP_NOT_WORD_BOUNDARY:
            case OP_WORD_BOUNDARY:
                cc += _pcre_OP_lengths[*cc];
                break;

                /* Handle literal characters */

            case OP_CHAR:
            case OP_CHARNC:
            case OP_NOT:
                branchlength++;
                cc += 2;
#ifdef SUPPORT_UTF8
                if ((options & PCRE_UTF8) != 0) {
                    while ((*cc & 0xc0) == 0x80)
                        cc++;
                }
#endif
                break;

                /* Handle exact repetitions. The count is already in characters,
                but we need to skip over a multibyte character in UTF8 mode.  */

            case OP_EXACT:
                branchlength += GET2(cc, 1);
                cc += 4;
#ifdef SUPPORT_UTF8
                if ((options & PCRE_UTF8) != 0) {
                    while ((*cc & 0x80) == 0x80)
                        cc++;
                }
#endif
                break;

            case OP_TYPEEXACT:
                branchlength += GET2(cc, 1);
                if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)
                    cc += 2;
                cc += 4;
                break;

                /* Handle single-char matchers */

            case OP_PROP:
            case OP_NOTPROP:
                cc += 2;
                /* Fall through */

            case OP_NOT_DIGIT:
            case OP_DIGIT:
            case OP_NOT_WHITESPACE:
            case OP_WHITESPACE:
            case OP_NOT_WORDCHAR:
            case OP_WORDCHAR:
            case OP_ANY:
                branchlength++;
                cc++;
                break;

                /* The single-byte matcher isn't allowed */

            case OP_ANYBYTE:
                return -2;

                /* Check a class for variable quantification */

#ifdef SUPPORT_UTF8
            case OP_XCLASS:
                cc += GET(cc, 1) - 33;
                /* Fall through */
#endif

            case OP_CLASS:
            case OP_NCLASS:
                cc += 33;

                switch (*cc) {
                    case OP_CRSTAR:
                    case OP_CRMINSTAR:
                    case OP_CRQUERY:
                    case OP_CRMINQUERY:
                        return -1;

                    case OP_CRRANGE:
                    case OP_CRMINRANGE:
                        if (GET2(cc, 1) != GET2(cc, 3))
                            return -1;
                        branchlength += GET2(cc, 1);
                        cc += 5;
                        break;

                    default:
                        branchlength++;
                }
                break;

                /* Anything else is variable length */

            default:
                return -1;
        }
    }
    /* Control never gets here */
}

/*************************************************
 *    Scan compiled regex for numbered bracket    *
 *************************************************/

/* This little function scans through a compiled pattern until it finds a
capturing bracket with the given number.

Arguments:
  code        points to start of expression
  utf8        TRUE in UTF-8 mode
  number      the required bracket number

Returns:      pointer to the opcode for the bracket, or NULL if not found
*/

static const uschar* find_bracket(const uschar* code, BOOL utf8, int number) {
    for (;;) {
        register int c = *code;
        if (c == OP_END)
            return NULL;

        /* XCLASS is used for classes that cannot be represented just by a bit
        map. This includes negated single high-valued characters. The length in
        the table is zero; the actual length is stored in the compiled code. */

        if (c == OP_XCLASS)
            code += GET(code, 1);

        /* Handle capturing bracket */

        else if (c == OP_CBRA) {
            int n = GET2(code, 1 + LINK_SIZE);
            if (n == number)
                return (uschar*)code;
            code += _pcre_OP_lengths[c];
        }

        /* Otherwise, we can get the item's length from the table, except that
        for repeated character types, we have to test for \p and \P, which have
        an extra two bytes of parameters. */

        else {
            switch (c) {
                case OP_TYPESTAR:
                case OP_TYPEMINSTAR:
                case OP_TYPEPLUS:
                case OP_TYPEMINPLUS:
                case OP_TYPEQUERY:
                case OP_TYPEMINQUERY:
                case OP_TYPEPOSSTAR:
                case OP_TYPEPOSPLUS:
                case OP_TYPEPOSQUERY:
                    if (code[1] == OP_PROP || code[1] == OP_NOTPROP)
                        code += 2;
                    break;

                case OP_TYPEUPTO:
                case OP_TYPEMINUPTO:
                case OP_TYPEEXACT:
                case OP_TYPEPOSUPTO:
                    if (code[3] == OP_PROP || code[3] == OP_NOTPROP)
                        code += 2;
                    break;
            }

            /* Add in the fixed length from the table */

            code += _pcre_OP_lengths[c];

            /* In UTF-8 mode, opcodes that are followed by a character may be
            followed by a multi-byte character. The length in the table is a
            minimum, so we have to arrange to skip the extra bytes. */

#ifdef SUPPORT_UTF8
            if (utf8)
                switch (c) {
                    case OP_CHAR:
                    case OP_CHARNC:
                    case OP_EXACT:
                    case OP_UPTO:
                    case OP_MINUPTO:
                    case OP_POSUPTO:
                    case OP_STAR:
                    case OP_MINSTAR:
                    case OP_POSSTAR:
                    case OP_PLUS:
                    case OP_MINPLUS:
                    case OP_POSPLUS:
                    case OP_QUERY:
                    case OP_MINQUERY:
                    case OP_POSQUERY:
                        if (code[-1] >= 0xc0)
                            code += _pcre_utf8_table4[code[-1] & 0x3f];
                        break;
                }
#endif
        }
    }
}

/*************************************************
 *   Scan compiled regex for recursion reference  *
 *************************************************/

/* This little function scans through a compiled pattern until it finds an
instance of OP_RECURSE.

Arguments:
  code        points to start of expression
  utf8        TRUE in UTF-8 mode

Returns:      pointer to the opcode for OP_RECURSE, or NULL if not found
*/

static const uschar* find_recurse(const uschar* code, BOOL utf8) {
    for (;;) {
        register int c = *code;
        if (c == OP_END)
            return NULL;
        if (c == OP_RECURSE)
            return code;

        /* XCLASS is used for classes that cannot be represented just by a bit
        map. This includes negated single high-valued characters. The length in
        the table is zero; the actual length is stored in the compiled code. */

        if (c == OP_XCLASS)
            code += GET(code, 1);

        /* Otherwise, we can get the item's length from the table, except that
        for repeated character types, we have to test for \p and \P, which have
        an extra two bytes of parameters. */

        else {
            switch (c) {
                case OP_TYPESTAR:
                case OP_TYPEMINSTAR:
                case OP_TYPEPLUS:
                case OP_TYPEMINPLUS:
                case OP_TYPEQUERY:
                case OP_TYPEMINQUERY:
                case OP_TYPEPOSSTAR:
                case OP_TYPEPOSPLUS:
                case OP_TYPEPOSQUERY:
                    if (code[1] == OP_PROP || code[1] == OP_NOTPROP)
                        code += 2;
                    break;

                case OP_TYPEPOSUPTO:
                case OP_TYPEUPTO:
                case OP_TYPEMINUPTO:
                case OP_TYPEEXACT:
                    if (code[3] == OP_PROP || code[3] == OP_NOTPROP)
                        code += 2;
                    break;
            }

            /* Add in the fixed length from the table */

            code += _pcre_OP_lengths[c];

            /* In UTF-8 mode, opcodes that are followed by a character may be
            followed by a multi-byte character. The length in the table is a
            minimum, so we have to arrange to skip the extra bytes. */

#ifdef SUPPORT_UTF8
            if (utf8)
                switch (c) {
                    case OP_CHAR:
                    case OP_CHARNC:
                    case OP_EXACT:
                    case OP_UPTO:
                    case OP_MINUPTO:
                    case OP_POSUPTO:
                    case OP_STAR:
                    case OP_MINSTAR:
                    case OP_POSSTAR:
                    case OP_PLUS:
                    case OP_MINPLUS:
                    case OP_POSPLUS:
                    case OP_QUERY:
                    case OP_MINQUERY:
                    case OP_POSQUERY:
                        if (code[-1] >= 0xc0)
                            code += _pcre_utf8_table4[code[-1] & 0x3f];
                        break;
                }
#endif
        }
    }
}

/*************************************************
 *    Scan compiled branch for non-emptiness      *
 *************************************************/

/* This function scans through a branch of a compiled pattern to see whether it
can match the empty string or not. It is called from could_be_empty()
below and from compile_branch() when checking for an unlimited repeat of a
group that can match nothing. Note that first_significant_code() skips over
backward and negative forward assertions when its final argument is TRUE. If we
hit an unclosed bracket, we return "empty" - this means we've struck an inner
bracket whose current branch will already have been scanned.

Arguments:
  code        points to start of search
  endcode     points to where to stop
  utf8        TRUE if in UTF8 mode

Returns:      TRUE if what is matched could be empty
*/

static BOOL could_be_empty_branch(const uschar* code,
                                  const uschar* endcode,
                                  BOOL utf8) {
    register int c;
    for (code = first_significant_code(code + _pcre_OP_lengths[*code], NULL, 0,
                                       TRUE);
         code < endcode; code = first_significant_code(
                             code + _pcre_OP_lengths[c], NULL, 0, TRUE)) {
        const uschar* ccode;

        c = *code;

        /* Skip over forward assertions; the other assertions are skipped by
        first_significant_code() with a TRUE final argument. */

        if (c == OP_ASSERT) {
            do
                code += GET(code, 1);
            while (*code == OP_ALT);
            c = *code;
            continue;
        }

        /* Groups with zero repeats can of course be empty; skip them. */

        if (c == OP_BRAZERO || c == OP_BRAMINZERO) {
            code += _pcre_OP_lengths[c];
            do
                code += GET(code, 1);
            while (*code == OP_ALT);
            c = *code;
            continue;
        }

        /* For other groups, scan the branches. */

        if (c == OP_BRA || c == OP_CBRA || c == OP_ONCE || c == OP_COND) {
            BOOL empty_branch;
            if (GET(code, 1) == 0)
                return TRUE; /* Hit unclosed bracket */

            /* Scan a closed bracket */

            empty_branch = FALSE;
            do {
                if (!empty_branch && could_be_empty_branch(code, endcode, utf8))
                    empty_branch = TRUE;
                code += GET(code, 1);
            } while (*code == OP_ALT);
            if (!empty_branch)
                return FALSE; /* All branches are non-empty */
            c = *code;
            continue;
        }

        /* Handle the other opcodes */

        switch (c) {
            /* Check for quantifiers after a class. XCLASS is used for classes
            that cannot be represented just by a bit map. This includes negated
            single high-valued characters. The length in _pcre_OP_lengths[] is
            zero; the actual length is stored in the compiled code, so we must
            update "code" here. */

#ifdef SUPPORT_UTF8
            case OP_XCLASS:
                ccode = code += GET(code, 1);
                goto CHECK_CLASS_REPEAT;
#endif

            case OP_CLASS:
            case OP_NCLASS:
                ccode = code + 33;

#ifdef SUPPORT_UTF8
            CHECK_CLASS_REPEAT:
#endif

                switch (*ccode) {
                    case OP_CRSTAR: /* These could be empty; continue */
                    case OP_CRMINSTAR:
                    case OP_CRQUERY:
                    case OP_CRMINQUERY:
                        break;

                    default:        /* Non-repeat => class must match */
                    case OP_CRPLUS: /* These repeats aren't empty */
                    case OP_CRMINPLUS:
                        return FALSE;

                    case OP_CRRANGE:
                    case OP_CRMINRANGE:
                        if (GET2(ccode, 1) > 0)
                            return FALSE; /* Minimum > 0 */
                        break;
                }
                break;

                /* Opcodes that must match a character */

            case OP_PROP:
            case OP_NOTPROP:
            case OP_EXTUNI:
            case OP_NOT_DIGIT:
            case OP_DIGIT:
            case OP_NOT_WHITESPACE:
            case OP_WHITESPACE:
            case OP_NOT_WORDCHAR:
            case OP_WORDCHAR:
            case OP_ANY:
            case OP_ANYBYTE:
            case OP_CHAR:
            case OP_CHARNC:
            case OP_NOT:
            case OP_PLUS:
            case OP_MINPLUS:
            case OP_POSPLUS:
            case OP_EXACT:
            case OP_NOTPLUS:
            case OP_NOTMINPLUS:
            case OP_NOTPOSPLUS:
            case OP_NOTEXACT:
            case OP_TYPEPLUS:
            case OP_TYPEMINPLUS:
            case OP_TYPEPOSPLUS:
            case OP_TYPEEXACT:
                return FALSE;

                /* These are going to continue, as they may be empty, but we
                have to fudge the length for the \p and \P cases. */

            case OP_TYPESTAR:
            case OP_TYPEMINSTAR:
            case OP_TYPEPOSSTAR:
            case OP_TYPEQUERY:
            case OP_TYPEMINQUERY:
            case OP_TYPEPOSQUERY:
                if (code[1] == OP_PROP || code[1] == OP_NOTPROP)
                    code += 2;
                break;

                /* Same for these */

            case OP_TYPEUPTO:
            case OP_TYPEMINUPTO:
            case OP_TYPEPOSUPTO:
                if (code[3] == OP_PROP || code[3] == OP_NOTPROP)
                    code += 2;
                break;

                /* End of branch */

            case OP_KET:
            case OP_KETRMAX:
            case OP_KETRMIN:
            case OP_ALT:
                return TRUE;

                /* In UTF-8 mode, STAR, MINSTAR, POSSTAR, QUERY, MINQUERY,
                POSQUERY, UPTO, MINUPTO, and POSUPTO may be followed by a
                multibyte character */

#ifdef SUPPORT_UTF8
            case OP_STAR:
            case OP_MINSTAR:
            case OP_POSSTAR:
            case OP_QUERY:
            case OP_MINQUERY:
            case OP_POSQUERY:
            case OP_UPTO:
            case OP_MINUPTO:
            case OP_POSUPTO:
                if (utf8)
                    while ((code[2] & 0xc0) == 0x80)
                        code++;
                break;
#endif
        }
    }

    return TRUE;
}

/*************************************************
 *    Scan compiled regex for non-emptiness       *
 *************************************************/

/* This function is called to check for left recursive calls. We want to check
the current branch of the current pattern to see if it could match the empty
string. If it could, we must look outwards for branches at other levels,
stopping when we pass beyond the bracket which is the subject of the recursion.

Arguments:
  code        points to start of the recursion
  endcode     points to where to stop (current RECURSE item)
  bcptr       points to the chain of current (unclosed) branch starts
  utf8        TRUE if in UTF-8 mode

Returns:      TRUE if what is matched could be empty
*/

static BOOL could_be_empty(const uschar* code,
                           const uschar* endcode,
                           branch_chain* bcptr,
                           BOOL utf8) {
    while (bcptr != NULL && bcptr->current >= code) {
        if (!could_be_empty_branch(bcptr->current, endcode, utf8))
            return FALSE;
        bcptr = bcptr->outer;
    }
    return TRUE;
}

/*************************************************
 *           Check for POSIX class syntax         *
 *************************************************/

/* This function is called when the sequence "[:" or "[." or "[=" is
encountered in a character class. It checks whether this is followed by a
sequence of characters terminated by a matching ":]" or ".]" or "=]". If we
reach an unescaped ']' without the special preceding character, return FALSE.

Originally, this function only recognized a sequence of letters between the
terminators, but it seems that Perl recognizes any sequence of characters,
though of course unknown POSIX names are subsequently rejected. Perl gives an
"Unknown POSIX class" error for [:f\oo:] for example, where previously PCRE
didn't consider this to be a POSIX class. Likewise for [:1234:].

The problem in trying to be exactly like Perl is in the handling of escapes. We
have to be sure that [abc[:x\]pqr] is *not* treated as containing a POSIX
class, but [abc[:x\]pqr:]] is (so that an error can be generated). The code
below handles the special case of \], but does not try to do any other escape
processing. This makes it different from Perl for cases such as [:l\ower:]
where Perl recognizes it as the POSIX class "lower" but PCRE does not recognize
"l\ower". This is a lesser evil that not diagnosing bad classes when Perl does,
I think.

Arguments:
  ptr      pointer to the initial [
  endptr   where to return the end pointer

Returns:   TRUE or FALSE
*/

static BOOL check_posix_syntax(const uschar* ptr, const uschar** endptr) {
    int terminator; /* Don't combine these lines; the Solaris cc */
    terminator =
        *(++ptr); /* compiler warns about "non-constant" initializer. */
    for (++ptr; *ptr != 0; ptr++) {
        if (*ptr == '\\' && ptr[1] == ']')
            ptr++;
        else {
            if (*ptr == ']')
                return FALSE;
            if (*ptr == terminator && ptr[1] == ']') {
                *endptr = ptr;
                return TRUE;
            }
        }
    }
    return FALSE;
}

/*************************************************
 *          Check POSIX class name                *
 *************************************************/

/* This function is called to check the name given in a POSIX-style class entry
such as [:alnum:].

Arguments:
  ptr        points to the first letter
  len        the length of the name

Returns:     a value representing the name, or -1 if unknown
*/

static int check_posix_name(const uschar* ptr, int len) {
    const char* pn = posix_names;
    register int yield = 0;
    while (posix_name_lengths[yield] != 0) {
        if (len == posix_name_lengths[yield] &&
            strncmp((const char*)ptr, pn, len) == 0)
            return yield;
        pn += posix_name_lengths[yield] + 1;
        yield++;
    }
    return -1;
}

/*************************************************
 *    Adjust OP_RECURSE items in repeated group   *
 *************************************************/

/* OP_RECURSE items contain an offset from the start of the regex to the group
that is referenced. This means that groups can be replicated for fixed
repetition simply by copying (because the recursion is allowed to refer to
earlier groups that are outside the current group). However, when a group is
optional (i.e. the minimum quantifier is zero), OP_BRAZERO is inserted before
it, after it has been compiled. This means that any OP_RECURSE items within it
that refer to the group itself or any contained groups have to have their
offsets adjusted. That one of the jobs of this function. Before it is called,
the partially compiled regex must be temporarily terminated with OP_END.

This function has been extended with the possibility of forward references for
recursions and subroutine calls. It must also check the list of such references
for the group we are dealing with. If it finds that one of the recursions in
the current group is on this list, it adjusts the offset in the list, not the
value in the reference (which is a group number).

Arguments:
  group      points to the start of the group
  adjust     the amount by which the group is to be moved
  utf8       TRUE in UTF-8 mode
  cd         contains pointers to tables etc.
  save_hwm   the hwm forward reference pointer at the start of the group

Returns:     nothing
*/

static void adjust_recurse(uschar* group,
                           int adjust,
                           BOOL utf8,
                           compile_data* cd,
                           uschar* save_hwm) {
    uschar* ptr = group;

    while ((ptr = (uschar*)find_recurse(ptr, utf8)) != NULL) {
        int offset;
        uschar* hc;

        /* See if this recursion is on the forward reference list. If so, adjust
        the reference. */

        for (hc = save_hwm; hc < cd->hwm; hc += LINK_SIZE) {
            offset = GET(hc, 0);
            if (cd->start_code + offset == ptr + 1) {
                PUT(hc, 0, offset + adjust);
                break;
            }
        }

        /* Otherwise, adjust the recursion offset if it's after the start of
        this group. */

        if (hc >= cd->hwm) {
            offset = GET(ptr, 1);
            if (cd->start_code + offset >= group)
                PUT(ptr, 1, offset + adjust);
        }

        ptr += 1 + LINK_SIZE;
    }
}

/*************************************************
 *        Insert an automatic callout point       *
 *************************************************/

/* This function is called when the PCRE_AUTO_CALLOUT option is set, to insert
callout points before each pattern item.

Arguments:
  code           current code pointer
  ptr            current pattern pointer
  cd             pointers to tables etc

Returns:         new code pointer
*/

static uschar* auto_callout(uschar* code, const uschar* ptr, compile_data* cd) {
    *code++ = OP_CALLOUT;
    *code++ = 255;
    PUT(code, 0, ptr - cd->start_pattern); /* Pattern offset */
    PUT(code, LINK_SIZE, 0);               /* Default length */
    return code + 2 * LINK_SIZE;
}

/*************************************************
 *         Complete a callout item                *
 *************************************************/

/* A callout item contains the length of the next item in the pattern, which
we can't fill in till after we have reached the relevant point. This is used
for both automatic and manual callouts.

Arguments:
  previous_callout   points to previous callout item
  ptr                current pattern pointer
  cd                 pointers to tables etc

Returns:             nothing
*/

static void complete_callout(uschar* previous_callout,
                             const uschar* ptr,
                             compile_data* cd) {
    int length = ptr - cd->start_pattern - GET(previous_callout, 2);
    PUT(previous_callout, 2 + LINK_SIZE, length);
}

#ifdef SUPPORT_UCP
/*************************************************
 *           Get othercase range                  *
 *************************************************/

/* This function is passed the start and end of a class range, in UTF-8 mode
with UCP support. It searches up the characters, looking for internal ranges of
characters in the "other" case. Each call returns the next one, updating the
start address.

Arguments:
  cptr        points to starting character value; updated
  d           end value
  ocptr       where to put start of othercase range
  odptr       where to put end of othercase range

Yield:        TRUE when range returned; FALSE when no more
*/

static BOOL get_othercase_range(unsigned int* cptr,
                                unsigned int d,
                                unsigned int* ocptr,
                                unsigned int* odptr) {
    unsigned int c, othercase, next;

    for (c = *cptr; c <= d; c++) {
        if ((othercase = _pcre_ucp_othercase(c)) != NOTACHAR)
            break;
    }

    if (c > d)
        return FALSE;

    *ocptr = othercase;
    next = othercase + 1;

    for (++c; c <= d; c++) {
        if (_pcre_ucp_othercase(c) != next)
            break;
        next++;
    }

    *odptr = next - 1;
    *cptr = c;

    return TRUE;
}
#endif /* SUPPORT_UCP */

/*************************************************
 *     Check if auto-possessifying is possible    *
 *************************************************/

/* This function is called for unlimited repeats of certain items, to see
whether the next thing could possibly match the repeated item. If not, it makes
sense to automatically possessify the repeated item.

Arguments:
  op_code       the repeated op code
  this          data for this item, depends on the opcode
  utf8          TRUE in UTF-8 mode
  utf8_char     used for utf8 character bytes, NULL if not relevant
  ptr           next character in pattern
  options       options bits
  cd            contains pointers to tables etc.

Returns:        TRUE if possessifying is wanted
*/

static BOOL check_auto_possessive(int op_code,
                                  int item,
                                  BOOL utf8,
                                  uschar* utf8_char,
                                  const uschar* ptr,
                                  int options,
                                  compile_data* cd) {
    int next;

    /* Skip whitespace and comments in extended mode */

    if ((options & PCRE_EXTENDED) != 0) {
        for (;;) {
            while ((cd->ctypes[*ptr] & ctype_space) != 0)
                ptr++;
            if (*ptr == '#') {
                while (*(++ptr) != 0)
                    if (IS_NEWLINE(ptr)) {
                        ptr += cd->nllen;
                        break;
                    }
            } else
                break;
        }
    }

    /* If the next item is one that we can handle, get its value. A non-negative
    value is a character, a negative value is an escape value. */

    if (*ptr == '\\') {
        int temperrorcode = 0;
        next = check_escape(&ptr, &temperrorcode, cd->bracount, options, FALSE);
        if (temperrorcode != 0)
            return FALSE;
        ptr++; /* Point after the escape sequence */
    }

    else if ((cd->ctypes[*ptr] & ctype_meta) == 0) {
#ifdef SUPPORT_UTF8
        if (utf8) {
            GETCHARINC(next, ptr);
        } else
#endif
            next = *ptr++;
    }

    else
        return FALSE;

    /* Skip whitespace and comments in extended mode */

    if ((options & PCRE_EXTENDED) != 0) {
        for (;;) {
            while ((cd->ctypes[*ptr] & ctype_space) != 0)
                ptr++;
            if (*ptr == '#') {
                while (*(++ptr) != 0)
                    if (IS_NEWLINE(ptr)) {
                        ptr += cd->nllen;
                        break;
                    }
            } else
                break;
        }
    }

    /* If the next thing is itself optional, we have to give up. */

    if (*ptr == '*' || *ptr == '?' || strncmp((char*)ptr, "{0,", 3) == 0)
        return FALSE;

    /* Now compare the next item with the previous opcode. If the previous is a
    positive single character match, "item" either contains the character or, if
    "item" is greater than 127 in utf8 mode, the character's bytes are in
    utf8_char. */

    /* Handle cases when the next item is a character. */

    if (next >= 0)
        switch (op_code) {
            case OP_CHAR:
#ifdef SUPPORT_UTF8
                if (utf8 && item > 127) {
                    GETCHAR(item, utf8_char);
                }
#endif
                return item != next;

                /* For CHARNC (caseless character) we must check the other case.
                If we have Unicode property support, we can use it to test the
                other case of high-valued characters. */

            case OP_CHARNC:
#ifdef SUPPORT_UTF8
                if (utf8 && item > 127) {
                    GETCHAR(item, utf8_char);
                }
#endif
                if (item == next)
                    return FALSE;
#ifdef SUPPORT_UTF8
                if (utf8) {
                    unsigned int othercase;
                    if (next < 128)
                        othercase = cd->fcc[next];
                    else
#ifdef SUPPORT_UCP
                        othercase = _pcre_ucp_othercase((unsigned int)next);
#else
                        othercase = NOTACHAR;
#endif
                    return (unsigned int)item != othercase;
                } else
#endif                                              /* SUPPORT_UTF8 */
                    return (item != cd->fcc[next]); /* Non-UTF-8 mode */

                /* For OP_NOT, "item" must be a single-byte character. */

            case OP_NOT:
                if (next < 0)
                    return FALSE; /* Not a character */
                if (item == next)
                    return TRUE;
                if ((options & PCRE_CASELESS) == 0)
                    return FALSE;
#ifdef SUPPORT_UTF8
                if (utf8) {
                    unsigned int othercase;
                    if (next < 128)
                        othercase = cd->fcc[next];
                    else
#ifdef SUPPORT_UCP
                        othercase = _pcre_ucp_othercase(next);
#else
                        othercase = NOTACHAR;
#endif
                    return (unsigned int)item == othercase;
                } else
#endif                                              /* SUPPORT_UTF8 */
                    return (item == cd->fcc[next]); /* Non-UTF-8 mode */

            case OP_DIGIT:
                return next > 127 || (cd->ctypes[next] & ctype_digit) == 0;

            case OP_NOT_DIGIT:
                return next <= 127 && (cd->ctypes[next] & ctype_digit) != 0;

            case OP_WHITESPACE:
                return next > 127 || (cd->ctypes[next] & ctype_space) == 0;

            case OP_NOT_WHITESPACE:
                return next <= 127 && (cd->ctypes[next] & ctype_space) != 0;

            case OP_WORDCHAR:
                return next > 127 || (cd->ctypes[next] & ctype_word) == 0;

            case OP_NOT_WORDCHAR:
                return next <= 127 && (cd->ctypes[next] & ctype_word) != 0;

            case OP_HSPACE:
            case OP_NOT_HSPACE:
                switch (next) {
                    case 0x09:
                    case 0x20:
                    case 0xa0:
                    case 0x1680:
                    case 0x180e:
                    case 0x2000:
                    case 0x2001:
                    case 0x2002:
                    case 0x2003:
                    case 0x2004:
                    case 0x2005:
                    case 0x2006:
                    case 0x2007:
                    case 0x2008:
                    case 0x2009:
                    case 0x200A:
                    case 0x202f:
                    case 0x205f:
                    case 0x3000:
                        return op_code != OP_HSPACE;
                    default:
                        return op_code == OP_HSPACE;
                }

            case OP_VSPACE:
            case OP_NOT_VSPACE:
                switch (next) {
                    case 0x0a:
                    case 0x0b:
                    case 0x0c:
                    case 0x0d:
                    case 0x85:
                    case 0x2028:
                    case 0x2029:
                        return op_code != OP_VSPACE;
                    default:
                        return op_code == OP_VSPACE;
                }

            default:
                return FALSE;
        }

    /* Handle the case when the next item is \d, \s, etc. */

    switch (op_code) {
        case OP_CHAR:
        case OP_CHARNC:
#ifdef SUPPORT_UTF8
            if (utf8 && item > 127) {
                GETCHAR(item, utf8_char);
            }
#endif
            switch (-next) {
                case ESC_d:
                    return item > 127 || (cd->ctypes[item] & ctype_digit) == 0;

                case ESC_D:
                    return item <= 127 && (cd->ctypes[item] & ctype_digit) != 0;

                case ESC_s:
                    return item > 127 || (cd->ctypes[item] & ctype_space) == 0;

                case ESC_S:
                    return item <= 127 && (cd->ctypes[item] & ctype_space) != 0;

                case ESC_w:
                    return item > 127 || (cd->ctypes[item] & ctype_word) == 0;

                case ESC_W:
                    return item <= 127 && (cd->ctypes[item] & ctype_word) != 0;

                case ESC_h:
                case ESC_H:
                    switch (item) {
                        case 0x09:
                        case 0x20:
                        case 0xa0:
                        case 0x1680:
                        case 0x180e:
                        case 0x2000:
                        case 0x2001:
                        case 0x2002:
                        case 0x2003:
                        case 0x2004:
                        case 0x2005:
                        case 0x2006:
                        case 0x2007:
                        case 0x2008:
                        case 0x2009:
                        case 0x200A:
                        case 0x202f:
                        case 0x205f:
                        case 0x3000:
                            return -next != ESC_h;
                        default:
                            return -next == ESC_h;
                    }

                case ESC_v:
                case ESC_V:
                    switch (item) {
                        case 0x0a:
                        case 0x0b:
                        case 0x0c:
                        case 0x0d:
                        case 0x85:
                        case 0x2028:
                        case 0x2029:
                            return -next != ESC_v;
                        default:
                            return -next == ESC_v;
                    }

                default:
                    return FALSE;
            }

        case OP_DIGIT:
            return next == -ESC_D || next == -ESC_s || next == -ESC_W ||
                   next == -ESC_h || next == -ESC_v;

        case OP_NOT_DIGIT:
            return next == -ESC_d;

        case OP_WHITESPACE:
            return next == -ESC_S || next == -ESC_d || next == -ESC_w;

        case OP_NOT_WHITESPACE:
            return next == -ESC_s || next == -ESC_h || next == -ESC_v;

        case OP_HSPACE:
            return next == -ESC_S || next == -ESC_H || next == -ESC_d ||
                   next == -ESC_w;

        case OP_NOT_HSPACE:
            return next == -ESC_h;

        /* Can't have \S in here because VT matches \S (Perl anomaly) */
        case OP_VSPACE:
            return next == -ESC_V || next == -ESC_d || next == -ESC_w;

        case OP_NOT_VSPACE:
            return next == -ESC_v;

        case OP_WORDCHAR:
            return next == -ESC_W || next == -ESC_s || next == -ESC_h ||
                   next == -ESC_v;

        case OP_NOT_WORDCHAR:
            return next == -ESC_w || next == -ESC_d;

        default:
            return FALSE;
    }

    /* Control does not reach here */
}

/*************************************************
 *           Compile one branch                   *
 *************************************************/

/* Scan the pattern, compiling it into the a vector. If the options are
changed during the branch, the pointer is used to change the external options
bits. This function is used during the pre-compile phase when we are trying
to find out the amount of memory needed, as well as during the real compile
phase. The value of lengthptr distinguishes the two phases.

Arguments:
  optionsptr     pointer to the option bits
  codeptr        points to the pointer to the current code point
  ptrptr         points to the current pattern pointer
  errorcodeptr   points to error code variable
  firstbyteptr   set to initial literal character, or < 0 (REQ_UNSET, REQ_NONE)
  reqbyteptr     set to the last literal character required, else < 0
  bcptr          points to current branch chain
  cd             contains pointers to tables etc.
  lengthptr      NULL during the real compile phase
                 points to length accumulator during pre-compile phase

Returns:         TRUE on success
                 FALSE, with *errorcodeptr set non-zero on error
*/

static BOOL compile_branch(int* optionsptr,
                           uschar** codeptr,
                           const uschar** ptrptr,
                           int* errorcodeptr,
                           int* firstbyteptr,
                           int* reqbyteptr,
                           branch_chain* bcptr,
                           compile_data* cd,
                           int* lengthptr) {
    int repeat_type, op_type;
    int repeat_min = 0, repeat_max = 0; /* To please picky compilers */
    int bravalue = 0;
    int greedy_default, greedy_non_default;
    int firstbyte, reqbyte;
    int zeroreqbyte, zerofirstbyte;
    int req_caseopt, reqvary, tempreqvary;
    int options = *optionsptr;
    int after_manual_callout = 0;
    int length_prevgroup = 0;
    register int c;
    register uschar* code = *codeptr;
    uschar* last_code = code;
    uschar* orig_code = code;
    uschar* tempcode;
    BOOL inescq = FALSE;
    BOOL groupsetfirstbyte = FALSE;
    const uschar* ptr = *ptrptr;
    const uschar* tempptr;
    uschar* previous = NULL;
    uschar* previous_callout = NULL;
    uschar* save_hwm = NULL;
    uschar classbits[32];

#ifdef SUPPORT_UTF8
    BOOL class_utf8;
    BOOL utf8 = (options & PCRE_UTF8) != 0;
    uschar* class_utf8data;
    uschar* class_utf8data_base;
    uschar utf8_char[6];
#else
    BOOL utf8 = FALSE;
    uschar* utf8_char = NULL;
#endif

#ifdef DEBUG
    if (lengthptr != NULL)
        DPRINTF((">> start branch\n"));
#endif

    /* Set up the default and non-default settings for greediness */

    greedy_default = ((options & PCRE_UNGREEDY) != 0);
    greedy_non_default = greedy_default ^ 1;

    /* Initialize no first byte, no required byte. REQ_UNSET means "no char
    matching encountered yet". It gets changed to REQ_NONE if we hit something
    that matches a non-fixed char first char; reqbyte just remains unset if we
    never find one.

    When we hit a repeat whose minimum is zero, we may have to adjust these
    values to take the zero repeat into account. This is implemented by setting
    them to zerofirstbyte and zeroreqbyte when such a repeat is encountered. The
    individual item types that can be repeated set these backoff variables
    appropriately. */

    firstbyte = reqbyte = zerofirstbyte = zeroreqbyte = REQ_UNSET;

    /* The variable req_caseopt contains either the REQ_CASELESS value or zero,
    according to the current setting of the caseless flag. REQ_CASELESS is a bit
    value > 255. It is added into the firstbyte or reqbyte variables to record
    the case status of the value. This is used only for ASCII characters. */

    req_caseopt = ((options & PCRE_CASELESS) != 0) ? REQ_CASELESS : 0;

    /* Switch on next character until the end of the branch */

    for (;; ptr++) {
        BOOL negate_class;
        BOOL should_flip_negation;
        BOOL possessive_quantifier;
        BOOL is_quantifier;
        BOOL is_recurse;
        BOOL reset_bracount;
        int class_charcount;
        int class_lastchar;
        int newoptions;
        int recno;
        int refsign;
        int skipbytes;
        int subreqbyte;
        int subfirstbyte;
        int terminator;
        int mclength;
        uschar mcbuffer[8];

        /* Get next byte in the pattern */

        c = *ptr;

        /* If we are in the pre-compile phase, accumulate the length used for
        the previous cycle of this loop. */

        if (lengthptr != NULL) {
#ifdef DEBUG
            if (code > cd->hwm)
                cd->hwm = code; /* High water info */
#endif
            if (code >
                cd->start_workspace + COMPILE_WORK_SIZE) /* Check for overrun */
            {
                *errorcodeptr = ERR52;
                goto FAILED;
            }

            /* There is at least one situation where code goes backwards: this
            is the case of a zero quantifier after a class (e.g. [ab]{0}). At
            compile time, the class is simply eliminated. However, it is created
            first, so we have to allow memory for it. Therefore, don't ever
            reduce the length at this point.
            */

            if (code < last_code)
                code = last_code;

            /* Paranoid check for integer overflow */

            if (OFLOW_MAX - *lengthptr < code - last_code) {
                *errorcodeptr = ERR20;
                goto FAILED;
            }

            *lengthptr += code - last_code;
            DPRINTF(
                ("length=%d added %d c=%c\n", *lengthptr, code - last_code, c));

            /* If "previous" is set and it is not at the start of the work
            space, move it back to there, in order to avoid filling up the work
            space. Otherwise, if "previous" is NULL, reset the current code
            pointer to the start. */

            if (previous != NULL) {
                if (previous > orig_code) {
                    memmove(orig_code, previous, code - previous);
                    code -= previous - orig_code;
                    previous = orig_code;
                }
            } else
                code = orig_code;

            /* Remember where this code item starts so we can pick up the length
            next time round. */

            last_code = code;
        }

        /* In the real compile phase, just check the workspace used by the
        forward reference list. */

        else if (cd->hwm > cd->start_workspace + COMPILE_WORK_SIZE) {
            *errorcodeptr = ERR52;
            goto FAILED;
        }

        /* If in \Q...\E, check for the end; if not, we have a literal */

        if (inescq && c != 0) {
            if (c == '\\' && ptr[1] == 'E') {
                inescq = FALSE;
                ptr++;
                continue;
            } else {
                if (previous_callout != NULL) {
                    if (lengthptr ==
                        NULL) /* Don't attempt in pre-compile phase */
                        complete_callout(previous_callout, ptr, cd);
                    previous_callout = NULL;
                }
                if ((options & PCRE_AUTO_CALLOUT) != 0) {
                    previous_callout = code;
                    code = auto_callout(code, ptr, cd);
                }
                goto NORMAL_CHAR;
            }
        }

        /* Fill in length of a previous callout, except when the next thing is
        a quantifier. */

        is_quantifier = c == '*' || c == '+' || c == '?' ||
                        (c == '{' && is_counted_repeat(ptr + 1));

        if (!is_quantifier && previous_callout != NULL &&
            after_manual_callout-- <= 0) {
            if (lengthptr == NULL) /* Don't attempt in pre-compile phase */
                complete_callout(previous_callout, ptr, cd);
            previous_callout = NULL;
        }

        /* In extended mode, skip white space and comments */

        if ((options & PCRE_EXTENDED) != 0) {
            if ((cd->ctypes[c] & ctype_space) != 0)
                continue;
            if (c == '#') {
                while (*(++ptr) != 0) {
                    if (IS_NEWLINE(ptr)) {
                        ptr += cd->nllen - 1;
                        break;
                    }
                }
                if (*ptr != 0)
                    continue;

                /* Else fall through to handle end of string */
                c = 0;
            }
        }

        /* No auto callout for quantifiers. */

        if ((options & PCRE_AUTO_CALLOUT) != 0 && !is_quantifier) {
            previous_callout = code;
            code = auto_callout(code, ptr, cd);
        }

        switch (c) {
            /* ===================================================================*/
            case 0:   /* The branch terminates at string end */
            case '|': /* or | or ) */
            case ')':
                *firstbyteptr = firstbyte;
                *reqbyteptr = reqbyte;
                *codeptr = code;
                *ptrptr = ptr;
                if (lengthptr != NULL) {
                    if (OFLOW_MAX - *lengthptr < code - last_code) {
                        *errorcodeptr = ERR20;
                        goto FAILED;
                    }
                    *lengthptr +=
                        code - last_code; /* To include callout length */
                    DPRINTF((">> end branch\n"));
                }
                return TRUE;

                /* ===================================================================*/
                /* Handle single-character metacharacters. In multiline mode, ^
                disables the setting of any following char as a first character.
              */

            case '^':
                if ((options & PCRE_MULTILINE) != 0) {
                    if (firstbyte == REQ_UNSET)
                        firstbyte = REQ_NONE;
                }
                previous = NULL;
                *code++ = OP_CIRC;
                break;

            case '$':
                previous = NULL;
                *code++ = OP_DOLL;
                break;

                /* There can never be a first char if '.' is first, whatever
                happens about repeats. The value of reqbyte doesn't change
                either. */

            case '.':
                if (firstbyte == REQ_UNSET)
                    firstbyte = REQ_NONE;
                zerofirstbyte = firstbyte;
                zeroreqbyte = reqbyte;
                previous = code;
                *code++ = OP_ANY;
                break;

                /* ===================================================================*/
                /* Character classes. If the included characters are all < 256,
                we build a 32-byte bitmap of the permitted characters, except in
                the special case where there is only one such character. For
                negated classes, we build the map as usual, then invert it at
                the end. However, we use a different opcode so that data
                characters > 255 can be handled correctly.

                If the class contains characters outside the 0-255 range, a
                different opcode is compiled. It may optionally have a bit map
                for characters < 256, but those above are are explicitly listed
                afterwards. A flag byte tells whether the bitmap is present, and
                whether this is a negated class or not.
                */

            case '[':
                previous = code;

                /* PCRE supports POSIX class stuff inside a class. Perl gives an
                error if they are encountered at the top level, so we'll do that
                too. */

                if ((ptr[1] == ':' || ptr[1] == '.' || ptr[1] == '=') &&
                    check_posix_syntax(ptr, &tempptr)) {
                    *errorcodeptr = (ptr[1] == ':') ? ERR13 : ERR31;
                    goto FAILED;
                }

                /* If the first character is '^', set the negation flag and skip
                it. Also, if the first few characters (either before or after ^)
                are \Q\E or \E we skip them too. This makes for compatibility
                with Perl. */

                negate_class = FALSE;
                for (;;) {
                    c = *(++ptr);
                    if (c == '\\') {
                        if (ptr[1] == 'E')
                            ptr++;
                        else if (strncmp((const char*)ptr + 1, "Q\\E", 3) == 0)
                            ptr += 3;
                        else
                            break;
                    } else if (!negate_class && c == '^')
                        negate_class = TRUE;
                    else
                        break;
                }

                /* If a class contains a negative special such as \S, we need to
                flip the negation flag at the end, so that support for
                characters > 255 works correctly (they are all included in the
                class). */

                should_flip_negation = FALSE;

                /* Keep a count of chars with values < 256 so that we can
                optimize the case of just a single character (as long as it's <
                256). However, For higher valued UTF-8 characters, we don't yet
                do any optimization. */

                class_charcount = 0;
                class_lastchar = -1;

                /* Initialize the 32-char bit map to all zeros. We build the map
                in a temporary bit of memory, in case the class contains only 1
                character (less than 256), because in that case the compiled
                code doesn't use the bit map.
                */

                memset(classbits, 0, 32 * sizeof(uschar));

#ifdef SUPPORT_UTF8
                class_utf8 = FALSE;                    /* No chars >= 256 */
                class_utf8data = code + LINK_SIZE + 2; /* For UTF-8 items */
                class_utf8data_base =
                    class_utf8data; /* For resetting in pass 1 */
#endif

                /* Process characters until ] is reached. By writing this as a
                "do" it means that an initial ] is taken as a data character. At
                the start of the loop, c contains the first byte of the
                character. */

                if (c != 0)
                    do {
                        const uschar* oldptr;

#ifdef SUPPORT_UTF8
                        if (utf8 &&
                            c > 127) { /* Braces are required because the */
                            GETCHARLEN(
                                c, ptr,
                                ptr); /* macro generates multiple statements */
                        }

                        /* In the pre-compile phase, accumulate the length of
                        any UTF-8 extra data and reset the pointer. This is so
                        that very large classes that contain a zillion UTF-8
                        characters no longer overwrite the work space (which is
                        on the stack). */

                        if (lengthptr != NULL) {
                            *lengthptr += class_utf8data - class_utf8data_base;
                            class_utf8data = class_utf8data_base;
                        }

#endif

                        /* Inside \Q...\E everything is literal except \E */

                        if (inescq) {
                            if (c == '\\' &&
                                ptr[1] == 'E') /* If we are at \E */
                            {
                                inescq = FALSE; /* Reset literal state */
                                ptr++;          /* Skip the 'E' */
                                continue;       /* Carry on with next */
                            }
                            goto CHECK_RANGE; /* Could be range if \E follows */
                        }

                        /* Handle POSIX class names. Perl allows a negation
                        extension of the form [:^name:]. A square bracket that
                        doesn't match the syntax is treated as a literal. We
                        also recognize the POSIX constructions
                        [.ch.] and [=ch=] ("collating elements") and fault them,
                        as Perl 5.6 and 5.8 do. */

                        if (c == '[' &&
                            (ptr[1] == ':' || ptr[1] == '.' || ptr[1] == '=') &&
                            check_posix_syntax(ptr, &tempptr)) {
                            BOOL local_negate = FALSE;
                            int posix_class, taboffset, tabopt;
                            register const uschar* cbits = cd->cbits;
                            uschar pbits[32];

                            if (ptr[1] != ':') {
                                *errorcodeptr = ERR31;
                                goto FAILED;
                            }

                            ptr += 2;
                            if (*ptr == '^') {
                                local_negate = TRUE;
                                should_flip_negation =
                                    TRUE; /* Note negative special */
                                ptr++;
                            }

                            posix_class = check_posix_name(ptr, tempptr - ptr);
                            if (posix_class < 0) {
                                *errorcodeptr = ERR30;
                                goto FAILED;
                            }

                            /* If matching is caseless, upper and lower are
                            converted to alpha. This relies on the fact that the
                            class table starts with alpha, lower, upper as the
                            first 3 entries. */

                            if ((options & PCRE_CASELESS) != 0 &&
                                posix_class <= 2)
                                posix_class = 0;

                            /* We build the bit map for the POSIX class in a
                            chunk of local store because we may be adding and
                            subtracting from it, and we don't want to subtract
                            bits that may be in the main map already. At the end
                            we or the result into the bit map that is being
                            built. */

                            posix_class *= 3;

                            /* Copy in the first table (always present) */

                            memcpy(pbits, cbits + posix_class_maps[posix_class],
                                   32 * sizeof(uschar));

                            /* If there is a second table, add or remove it as
                             * required. */

                            taboffset = posix_class_maps[posix_class + 1];
                            tabopt = posix_class_maps[posix_class + 2];

                            if (taboffset >= 0) {
                                if (tabopt >= 0)
                                    for (c = 0; c < 32; c++)
                                        pbits[c] |= cbits[c + taboffset];
                                else
                                    for (c = 0; c < 32; c++)
                                        pbits[c] &= ~cbits[c + taboffset];
                            }

                            /* Not see if we need to remove any special
                            characters. An option value of 1 removes vertical
                            space and 2 removes underscore. */

                            if (tabopt < 0)
                                tabopt = -tabopt;
                            if (tabopt == 1)
                                pbits[1] &= ~0x3c;
                            else if (tabopt == 2)
                                pbits[11] &= 0x7f;

                            /* Add the POSIX table or its complement into the
                            main table that is being built and we are done. */

                            if (local_negate)
                                for (c = 0; c < 32; c++)
                                    classbits[c] |= ~pbits[c];
                            else
                                for (c = 0; c < 32; c++)
                                    classbits[c] |= pbits[c];

                            ptr = tempptr + 1;
                            class_charcount =
                                10; /* Set > 1; assumes more than 1 per class */
                            continue; /* End of POSIX syntax handling */
                        }

                        /* Backslash may introduce a single character, or it may
                        introduce one of the specials, which just set a flag.
                        The sequence \b is a special case. Inside a class (and
                        only there) it is treated as backspace. Elsewhere it
                        marks a word boundary. Other escapes have preset maps
                        ready to 'or' into the one we are building. We assume
                        they have more than one character in them, so set
                        class_charcount bigger than one. */

                        if (c == '\\') {
                            c = check_escape(&ptr, errorcodeptr, cd->bracount,
                                             options, TRUE);
                            if (*errorcodeptr != 0)
                                goto FAILED;

                            if (-c == ESC_b)
                                c = '\b'; /* \b is backspace in a class */
                            else if (-c == ESC_X)
                                c = 'X'; /* \X is literal X in a class */
                            else if (-c == ESC_R)
                                c = 'R'; /* \R is literal R in a class */
                            else if (-c ==
                                     ESC_Q) /* Handle start of quoted string */
                            {
                                if (ptr[1] == '\\' && ptr[2] == 'E') {
                                    ptr += 2; /* avoid empty string */
                                } else
                                    inescq = TRUE;
                                continue;
                            } else if (-c == ESC_E)
                                continue; /* Ignore orphan \E */

                            if (c < 0) {
                                register const uschar* cbits = cd->cbits;
                                class_charcount +=
                                    2; /* Greater than 1 is what matters */

                                /* Save time by not doing this in the
                                 * pre-compile phase. */

                                if (lengthptr == NULL)
                                    switch (-c) {
                                        case ESC_d:
                                            for (c = 0; c < 32; c++)
                                                classbits[c] |=
                                                    cbits[c + cbit_digit];
                                            continue;

                                        case ESC_D:
                                            should_flip_negation = TRUE;
                                            for (c = 0; c < 32; c++)
                                                classbits[c] |=
                                                    ~cbits[c + cbit_digit];
                                            continue;

                                        case ESC_w:
                                            for (c = 0; c < 32; c++)
                                                classbits[c] |=
                                                    cbits[c + cbit_word];
                                            continue;

                                        case ESC_W:
                                            should_flip_negation = TRUE;
                                            for (c = 0; c < 32; c++)
                                                classbits[c] |=
                                                    ~cbits[c + cbit_word];
                                            continue;

                                        case ESC_s:
                                            for (c = 0; c < 32; c++)
                                                classbits[c] |=
                                                    cbits[c + cbit_space];
                                            classbits[1] &=
                                                ~0x08; /* Perl 5.004 onwards
                                                          omits VT from \s */
                                            continue;

                                        case ESC_S:
                                            should_flip_negation = TRUE;
                                            for (c = 0; c < 32; c++)
                                                classbits[c] |=
                                                    ~cbits[c + cbit_space];
                                            classbits[1] |=
                                                0x08; /* Perl 5.004 onwards
                                                         omits VT from \s */
                                            continue;

                                        default: /* Not recognized; fall through
                                                  */
                                            break; /* Need "default" setting to
                                                      stop compiler warning. */
                                    }

                                /* In the pre-compile phase, just do the
                                 * recognition. */

                                else if (c == -ESC_d || c == -ESC_D ||
                                         c == -ESC_w || c == -ESC_W ||
                                         c == -ESC_s || c == -ESC_S)
                                    continue;

                                /* We need to deal with \H, \h, \V, and \v in
                                both phases because they use extra memory. */

                                if (-c == ESC_h) {
                                    SETBIT(classbits, 0x09); /* VT */
                                    SETBIT(classbits, 0x20); /* SPACE */
                                    SETBIT(classbits, 0xa0); /* NSBP */
#ifdef SUPPORT_UTF8
                                    if (utf8) {
                                        class_utf8 = TRUE;
                                        *class_utf8data++ = XCL_SINGLE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x1680, class_utf8data);
                                        *class_utf8data++ = XCL_SINGLE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x180e, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2000, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x200A, class_utf8data);
                                        *class_utf8data++ = XCL_SINGLE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x202f, class_utf8data);
                                        *class_utf8data++ = XCL_SINGLE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x205f, class_utf8data);
                                        *class_utf8data++ = XCL_SINGLE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x3000, class_utf8data);
                                    }
#endif
                                    continue;
                                }

                                if (-c == ESC_H) {
                                    for (c = 0; c < 32; c++) {
                                        int x = 0xff;
                                        switch (c) {
                                            case 0x09 / 8:
                                                x ^= 1 << (0x09 % 8);
                                                break;
                                            case 0x20 / 8:
                                                x ^= 1 << (0x20 % 8);
                                                break;
                                            case 0xa0 / 8:
                                                x ^= 1 << (0xa0 % 8);
                                                break;
                                            default:
                                                break;
                                        }
                                        classbits[c] |= x;
                                    }

#ifdef SUPPORT_UTF8
                                    if (utf8) {
                                        class_utf8 = TRUE;
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x0100, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x167f, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x1681, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x180d, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x180f, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x1fff, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x200B, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x202e, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2030, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x205e, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2060, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2fff, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x3001, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x7fffffff, class_utf8data);
                                    }
#endif
                                    continue;
                                }

                                if (-c == ESC_v) {
                                    SETBIT(classbits, 0x0a); /* LF */
                                    SETBIT(classbits, 0x0b); /* VT */
                                    SETBIT(classbits, 0x0c); /* FF */
                                    SETBIT(classbits, 0x0d); /* CR */
                                    SETBIT(classbits, 0x85); /* NEL */
#ifdef SUPPORT_UTF8
                                    if (utf8) {
                                        class_utf8 = TRUE;
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2028, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2029, class_utf8data);
                                    }
#endif
                                    continue;
                                }

                                if (-c == ESC_V) {
                                    for (c = 0; c < 32; c++) {
                                        int x = 0xff;
                                        switch (c) {
                                            case 0x0a / 8:
                                                x ^= 1 << (0x0a % 8);
                                                x ^= 1 << (0x0b % 8);
                                                x ^= 1 << (0x0c % 8);
                                                x ^= 1 << (0x0d % 8);
                                                break;
                                            case 0x85 / 8:
                                                x ^= 1 << (0x85 % 8);
                                                break;
                                            default:
                                                break;
                                        }
                                        classbits[c] |= x;
                                    }

#ifdef SUPPORT_UTF8
                                    if (utf8) {
                                        class_utf8 = TRUE;
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x0100, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2027, class_utf8data);
                                        *class_utf8data++ = XCL_RANGE;
                                        class_utf8data += _pcre_ord2utf8(
                                            0x2029, class_utf8data);
                                        class_utf8data += _pcre_ord2utf8(
                                            0x7fffffff, class_utf8data);
                                    }
#endif
                                    continue;
                                }

                                /* We need to deal with \P and \p in both
                                 * phases. */

#ifdef SUPPORT_UCP
                                if (-c == ESC_p || -c == ESC_P) {
                                    BOOL negated;
                                    int pdata;
                                    int ptype = get_ucp(&ptr, &negated, &pdata,
                                                        errorcodeptr);
                                    if (ptype < 0)
                                        goto FAILED;
                                    class_utf8 = TRUE;
                                    *class_utf8data++ =
                                        ((-c == ESC_p) != negated)
                                            ? XCL_PROP
                                            : XCL_NOTPROP;
                                    *class_utf8data++ = ptype;
                                    *class_utf8data++ = pdata;
                                    class_charcount -=
                                        2; /* Not a < 256 character */
                                    continue;
                                }
#endif
                                /* Unrecognized escapes are faulted if PCRE is
                                running in its strict mode. By default, for
                                compatibility with Perl, they are treated as
                                literals. */

                                if ((options & PCRE_EXTRA) != 0) {
                                    *errorcodeptr = ERR7;
                                    goto FAILED;
                                }

                                class_charcount -=
                                    2; /* Undo the default count from above */
                                c = *ptr; /* Get the final character and fall
                                             through */
                            }

                            /* Fall through if we have a single character (c >=
                            0). This may be greater than 256 in UTF-8 mode. */

                        } /* End of backslash handling */

                        /* A single character may be followed by '-' to form a
                        range. However, Perl does not permit ']' to be the end
                        of the range. A '-' character at the end is treated as a
                        literal. Perl ignores orphaned \E sequences entirely.
                        The code for handling \Q and \E is messy. */

                    CHECK_RANGE:
                        while (ptr[1] == '\\' && ptr[2] == 'E') {
                            inescq = FALSE;
                            ptr += 2;
                        }

                        oldptr = ptr;

                        /* Remember \r or \n */

                        if (c == '\r' || c == '\n')
                            cd->external_flags |= PCRE_HASCRORLF;

                        /* Check for range */

                        if (!inescq && ptr[1] == '-') {
                            int d;
                            ptr += 2;
                            while (*ptr == '\\' && ptr[1] == 'E')
                                ptr += 2;

                            /* If we hit \Q (not followed by \E) at this point,
                            go into escaped mode. */

                            while (*ptr == '\\' && ptr[1] == 'Q') {
                                ptr += 2;
                                if (*ptr == '\\' && ptr[1] == 'E') {
                                    ptr += 2;
                                    continue;
                                }
                                inescq = TRUE;
                                break;
                            }

                            if (*ptr == 0 || (!inescq && *ptr == ']')) {
                                ptr = oldptr;
                                goto LONE_SINGLE_CHARACTER;
                            }

#ifdef SUPPORT_UTF8
                            if (utf8) { /* Braces are required because the */
                                GETCHARLEN(d, ptr,
                                           ptr); /* macro generates multiple
                                                    statements */
                            } else
#endif
                                d = *ptr; /* Not UTF-8 mode */

                            /* The second part of a range can be a
                            single-character escape, but not any of the other
                            escapes. Perl 5.6 treats a hyphen as a literal in
                            such circumstances. */

                            if (!inescq && d == '\\') {
                                d = check_escape(&ptr, errorcodeptr,
                                                 cd->bracount, options, TRUE);
                                if (*errorcodeptr != 0)
                                    goto FAILED;

                                /* \b is backspace; \X is literal X; \R is
                                literal R; any other special means the '-' was
                                literal */

                                if (d < 0) {
                                    if (d == -ESC_b)
                                        d = '\b';
                                    else if (d == -ESC_X)
                                        d = 'X';
                                    else if (d == -ESC_R)
                                        d = 'R';
                                    else {
                                        ptr = oldptr;
                                        goto LONE_SINGLE_CHARACTER; /* A few
                                                                       lines
                                                                       below */
                                    }
                                }
                            }

                            /* Check that the two values are in the correct
                            order. Optimize one-character ranges */

                            if (d < c) {
                                *errorcodeptr = ERR8;
                                goto FAILED;
                            }

                            if (d == c)
                                goto LONE_SINGLE_CHARACTER; /* A few lines below
                                                             */

                            /* Remember \r or \n */

                            if (d == '\r' || d == '\n')
                                cd->external_flags |= PCRE_HASCRORLF;

                                /* In UTF-8 mode, if the upper limit is > 255,
                                or > 127 for caseless matching, we have to use
                                an XCLASS with extra data items. Caseless
                                matching for characters > 127 is available only
                                if UCP support is available. */

#ifdef SUPPORT_UTF8
                            if (utf8 &&
                                (d > 255 ||
                                 ((options & PCRE_CASELESS) != 0 && d > 127))) {
                                class_utf8 = TRUE;

                                /* With UCP support, we can find the other case
                                equivalents of the relevant characters. There
                                may be several ranges. Optimize how they fit
                                with the basic range. */

#ifdef SUPPORT_UCP
                                if ((options & PCRE_CASELESS) != 0) {
                                    unsigned int occ, ocd;
                                    unsigned int cc = c;
                                    unsigned int origd = d;
                                    while (get_othercase_range(&cc, origd, &occ,
                                                               &ocd)) {
                                        if (occ >= (unsigned int)c &&
                                            ocd <= (unsigned int)d)
                                            continue; /* Skip embedded ranges */

                                        if (occ < (unsigned int)c &&
                                            ocd >= (unsigned int)c -
                                                       1) /* Extend the basic
                                                             range */
                                        { /* if there is overlap,   */
                                            c = occ;  /* noting that if occ < c
                                                       */
                                            continue; /* we can't have ocd > d
                                                       */
                                        } /* because a subrange is  */
                                        if (ocd > (unsigned int)d &&
                                            occ <=
                                                (unsigned int)d +
                                                    1) /* always shorter than */
                                        { /* the basic range.       */
                                            d = ocd;
                                            continue;
                                        }

                                        if (occ == ocd) {
                                            *class_utf8data++ = XCL_SINGLE;
                                        } else {
                                            *class_utf8data++ = XCL_RANGE;
                                            class_utf8data += _pcre_ord2utf8(
                                                occ, class_utf8data);
                                        }
                                        class_utf8data +=
                                            _pcre_ord2utf8(ocd, class_utf8data);
                                    }
                                }
#endif /* SUPPORT_UCP */

                                /* Now record the original range, possibly
                                modified for UCP caseless overlapping ranges. */

                                *class_utf8data++ = XCL_RANGE;
                                class_utf8data +=
                                    _pcre_ord2utf8(c, class_utf8data);
                                class_utf8data +=
                                    _pcre_ord2utf8(d, class_utf8data);

                                /* With UCP support, we are done. Without UCP
                                support, there is no caseless matching for UTF-8
                                characters > 127; we can use the bit map for the
                                smaller ones. */

#ifdef SUPPORT_UCP
                                continue; /* With next character in the class */
#else
                                if ((options & PCRE_CASELESS) == 0 || c > 127)
                                    continue;

                                /* Adjust upper limit and fall through to set up
                                 * the map */

                                d = 127;

#endif /* SUPPORT_UCP */
                            }
#endif /* SUPPORT_UTF8 */

                            /* We use the bit map for all cases when not in
                            UTF-8 mode; else ranges that lie entirely within
                            0-127 when there is UCP support; else for partial
                            ranges without UCP support. */

                            class_charcount += d - c + 1;
                            class_lastchar = d;

                            /* We can save a bit of time by skipping this in the
                             * pre-compile. */

                            if (lengthptr == NULL)
                                for (; c <= d; c++) {
                                    classbits[c / 8] |= (1 << (c & 7));
                                    if ((options & PCRE_CASELESS) != 0) {
                                        int uc = cd->fcc[c]; /* flip case */
                                        classbits[uc / 8] |= (1 << (uc & 7));
                                    }
                                }

                            continue; /* Go get the next char in the class */
                        }

                        /* Handle a lone single character - we can get here for
                        a normal non-escape char, or after \ that introduces a
                        single character or for an apparent range that isn't. */

                    LONE_SINGLE_CHARACTER:

                        /* Handle a character that cannot go in the bit map */

#ifdef SUPPORT_UTF8
                        if (utf8 &&
                            (c > 255 ||
                             ((options & PCRE_CASELESS) != 0 && c > 127))) {
                            class_utf8 = TRUE;
                            *class_utf8data++ = XCL_SINGLE;
                            class_utf8data += _pcre_ord2utf8(c, class_utf8data);

#ifdef SUPPORT_UCP
                            if ((options & PCRE_CASELESS) != 0) {
                                unsigned int othercase;
                                if ((othercase = _pcre_ucp_othercase(c)) !=
                                    NOTACHAR) {
                                    *class_utf8data++ = XCL_SINGLE;
                                    class_utf8data += _pcre_ord2utf8(
                                        othercase, class_utf8data);
                                }
                            }
#endif /* SUPPORT_UCP */

                        } else
#endif /* SUPPORT_UTF8 */

                        /* Handle a single-byte character */
                        {
                            classbits[c / 8] |= (1 << (c & 7));
                            if ((options & PCRE_CASELESS) != 0) {
                                c = cd->fcc[c]; /* flip case */
                                classbits[c / 8] |= (1 << (c & 7));
                            }
                            class_charcount++;
                            class_lastchar = c;
                        }
                    }

                    /* Loop until ']' reached. This "while" is the end of the
                       "do" above. */

                    while ((c = *(++ptr)) != 0 && (c != ']' || inescq));

                if (c == 0) /* Missing terminating ']' */
                {
                    *errorcodeptr = ERR6;
                    goto FAILED;
                }

                /* This code has been disabled because it would mean that \s
                counts as an explicit \r or \n reference, and that's not really
                what is wanted. Now we set the flag only if there is a literal
                "\r" or "\n" in the class. */

#if 0
    /* Remember whether \r or \n are in this class */

    if (negate_class)
      {
      if ((classbits[1] & 0x24) != 0x24) cd->external_flags |= PCRE_HASCRORLF;
      }
    else
      {
      if ((classbits[1] & 0x24) != 0) cd->external_flags |= PCRE_HASCRORLF;
      }
#endif

                /* If class_charcount is 1, we saw precisely one character whose
                value is less than 256. As long as there were no characters >=
                128 and there was no use of \p or \P, in other words, no use of
                any XCLASS features, we can optimize.

                In UTF-8 mode, we can optimize the negative case only if there
                were no characters >= 128 because OP_NOT and the related opcodes
                like OP_NOTSTAR operate on single-bytes only. This is an
                historical hangover. Maybe one day we can tidy these opcodes to
                handle multi-byte characters.

                The optimization throws away the bit map. We turn the item into
                a 1-character OP_CHAR[NC] if it's positive, or OP_NOT if it's
                negative. Note that OP_NOT does not support multibyte
                characters. In the positive case, it can cause firstbyte to be
                set. Otherwise, there can be no first char if this item is
                first, whatever repeat count may follow. In the case of reqbyte,
                save the previous value for reinstating. */

#ifdef SUPPORT_UTF8
                if (class_charcount == 1 && !class_utf8 &&
                    (!utf8 || !negate_class || class_lastchar < 128))
#else
                if (class_charcount == 1)
#endif
                {
                    zeroreqbyte = reqbyte;

                    /* The OP_NOT opcode works on one-byte characters only. */

                    if (negate_class) {
                        if (firstbyte == REQ_UNSET)
                            firstbyte = REQ_NONE;
                        zerofirstbyte = firstbyte;
                        *code++ = OP_NOT;
                        *code++ = class_lastchar;
                        break;
                    }

                    /* For a single, positive character, get the value into
                    mcbuffer, and then we can handle this with the normal
                    one-character code. */

#ifdef SUPPORT_UTF8
                    if (utf8 && class_lastchar > 127)
                        mclength = _pcre_ord2utf8(class_lastchar, mcbuffer);
                    else
#endif
                    {
                        mcbuffer[0] = class_lastchar;
                        mclength = 1;
                    }
                    goto ONE_CHAR;
                } /* End of 1-char optimization */

                /* The general case - not the one-char optimization. If this is
                the first thing in the branch, there can be no first char
                setting, whatever the repeat count. Any reqbyte setting must
                remain unchanged after any kind of repeat. */

                if (firstbyte == REQ_UNSET)
                    firstbyte = REQ_NONE;
                zerofirstbyte = firstbyte;
                zeroreqbyte = reqbyte;

                /* If there are characters with values > 255, we have to compile
                an extended class, with its own opcode, unless there was a
                negated special such as \S in the class, because in that case
                all characters > 255 are in the class, so any that were
                explicitly given as well can be ignored. If (when there are
                explicit characters > 255 that must be listed) there are no
                characters < 256, we can omit the bitmap in the actual compiled
                code. */

#ifdef SUPPORT_UTF8
                if (class_utf8 && !should_flip_negation) {
                    *class_utf8data++ =
                        XCL_END; /* Marks the end of extra data */
                    *code++ = OP_XCLASS;
                    code += LINK_SIZE;
                    *code = negate_class ? XCL_NOT : 0;

                    /* If the map is required, move up the extra data to make
                    room for it; otherwise just move the code pointer to the end
                    of the extra data. */

                    if (class_charcount > 0) {
                        *code++ |= XCL_MAP;
                        memmove(code + 32, code, class_utf8data - code);
                        memcpy(code, classbits, 32);
                        code = class_utf8data + 32;
                    } else
                        code = class_utf8data;

                    /* Now fill in the complete length of the item */

                    PUT(previous, 1, code - previous);
                    break; /* End of class handling */
                }
#endif

                /* If there are no characters > 255, set the opcode to OP_CLASS
                or OP_NCLASS, depending on whether the whole class was negated
                and whether there were negative specials such as \S in the
                class. Then copy the 32-byte map into the code vector, negating
                it if necessary. */

                *code++ = (negate_class == should_flip_negation) ? OP_CLASS
                                                                 : OP_NCLASS;
                if (negate_class) {
                    if (lengthptr ==
                        NULL) /* Save time in the pre-compile phase */
                        for (c = 0; c < 32; c++)
                            code[c] = ~classbits[c];
                } else {
                    memcpy(code, classbits, 32);
                }
                code += 32;
                break;

                /* ===================================================================*/
                /* Various kinds of repeat; '{' is not necessarily a quantifier,
                but this has been tested above. */

            case '{':
                if (!is_quantifier)
                    goto NORMAL_CHAR;
                ptr = read_repeat_counts(ptr + 1, &repeat_min, &repeat_max,
                                         errorcodeptr);
                if (*errorcodeptr != 0)
                    goto FAILED;
                goto REPEAT;

            case '*':
                repeat_min = 0;
                repeat_max = -1;
                goto REPEAT;

            case '+':
                repeat_min = 1;
                repeat_max = -1;
                goto REPEAT;

            case '?':
                repeat_min = 0;
                repeat_max = 1;

            REPEAT:
                if (previous == NULL) {
                    *errorcodeptr = ERR9;
                    goto FAILED;
                }

                if (repeat_min == 0) {
                    firstbyte = zerofirstbyte; /* Adjust for zero repeat */
                    reqbyte = zeroreqbyte;     /* Ditto */
                }

                /* Remember whether this is a variable length repeat */

                reqvary = (repeat_min == repeat_max) ? 0 : REQ_VARY;

                op_type = 0; /* Default single-char op codes */
                possessive_quantifier =
                    FALSE; /* Default not possessive quantifier */

                /* Save start of previous item, in case we have to move it up to
                make space for an inserted OP_ONCE for the additional '+'
                extension. */

                tempcode = previous;

                /* If the next character is '+', we have a possessive
                quantifier. This implies greediness, whatever the setting of the
                PCRE_UNGREEDY option. If the next character is '?' this is a
                minimizing repeat, by default, but if PCRE_UNGREEDY is set, it
                works the other way round. We change the repeat type to the
                non-default. */

                if (ptr[1] == '+') {
                    repeat_type = 0; /* Force greedy */
                    possessive_quantifier = TRUE;
                    ptr++;
                } else if (ptr[1] == '?') {
                    repeat_type = greedy_non_default;
                    ptr++;
                } else
                    repeat_type = greedy_default;

                /* If previous was a character match, abolish the item and
                generate a repeat item instead. If a char item has a minumum of
                more than one, ensure that it is set in reqbyte - it might not
                be if a sequence such as x{3} is the first thing in a branch
                because the x will have gone into firstbyte instead.  */

                if (*previous == OP_CHAR || *previous == OP_CHARNC) {
                    /* Deal with UTF-8 characters that take up more than one
                    byte. It's easier to write this out separately than try to
                    macrify it. Use c to hold the length of the character in
                    bytes, plus 0x80 to flag that it's a length rather than a
                    small character. */

#ifdef SUPPORT_UTF8
                    if (utf8 && (code[-1] & 0x80) != 0) {
                        uschar* lastchar = code - 1;
                        while ((*lastchar & 0xc0) == 0x80)
                            lastchar--;
                        c = code - lastchar; /* Length of UTF-8 character */
                        memcpy(utf8_char, lastchar, c); /* Save the char */
                        c |= 0x80;                      /* Flag c as a length */
                    } else
#endif

                    /* Handle the case of a single byte - either with no UTF8
                    support, or with UTF-8 disabled, or for a UTF-8 character <
                    128. */

                    {
                        c = code[-1];
                        if (repeat_min > 1)
                            reqbyte = c | req_caseopt | cd->req_varyopt;
                    }

                    /* If the repetition is unlimited, it pays to see if the
                    next thing on the line is something that cannot possibly
                    match this character. If so, automatically possessifying
                    this item gains some performance in the case where the match
                    fails. */

                    if (!possessive_quantifier && repeat_max < 0 &&
                        check_auto_possessive(*previous, c, utf8, utf8_char,
                                              ptr + 1, options, cd)) {
                        repeat_type = 0; /* Force greedy */
                        possessive_quantifier = TRUE;
                    }

                    goto OUTPUT_SINGLE_REPEAT; /* Code shared with single
                                                  character types */
                }

                /* If previous was a single negated character ([^a] or similar),
                we use one of the special opcodes, replacing it. The code is
                shared with single- character repeats by setting opt_type to add
                a suitable offset into repeat_type. We can also test for
                auto-possessification. OP_NOT is currently used only for
                single-byte chars. */

                else if (*previous == OP_NOT) {
                    op_type = OP_NOTSTAR - OP_STAR; /* Use "not" opcodes */
                    c = previous[1];
                    if (!possessive_quantifier && repeat_max < 0 &&
                        check_auto_possessive(OP_NOT, c, utf8, NULL, ptr + 1,
                                              options, cd)) {
                        repeat_type = 0; /* Force greedy */
                        possessive_quantifier = TRUE;
                    }
                    goto OUTPUT_SINGLE_REPEAT;
                }

                /* If previous was a character type match (\d or similar),
                abolish it and create a suitable repeat item. The code is shared
                with single-character repeats by setting op_type to add a
                suitable offset into repeat_type. Note the the Unicode property
                types will be present only when SUPPORT_UCP is defined, but we
                don't wrap the little bits of code here because it just makes it
                horribly messy. */

                else if (*previous < OP_EODN) {
                    uschar* oldcode;
                    int prop_type, prop_value;
                    op_type = OP_TYPESTAR - OP_STAR; /* Use type opcodes */
                    c = *previous;

                    if (!possessive_quantifier && repeat_max < 0 &&
                        check_auto_possessive(c, 0, utf8, NULL, ptr + 1,
                                              options, cd)) {
                        repeat_type = 0; /* Force greedy */
                        possessive_quantifier = TRUE;
                    }

                OUTPUT_SINGLE_REPEAT:
                    if (*previous == OP_PROP || *previous == OP_NOTPROP) {
                        prop_type = previous[1];
                        prop_value = previous[2];
                    } else
                        prop_type = prop_value = -1;

                    oldcode = code;
                    code = previous; /* Usually overwrite previous item */

                    /* If the maximum is zero then the minimum must also be
                    zero; Perl allows this case, so we do too - by simply
                    omitting the item altogether. */

                    if (repeat_max == 0)
                        goto END_REPEAT;

                    /* All real repeats make it impossible to handle partial
                    matching (maybe one day we will be able to remove this
                    restriction). */

                    if (repeat_max != 1)
                        cd->external_flags |= PCRE_NOPARTIAL;

                    /* Combine the op_type with the repeat_type */

                    repeat_type += op_type;

                    /* A minimum of zero is handled either as the special case *
                    or ?, or as an UPTO, with the maximum given. */

                    if (repeat_min == 0) {
                        if (repeat_max == -1)
                            *code++ = OP_STAR + repeat_type;
                        else if (repeat_max == 1)
                            *code++ = OP_QUERY + repeat_type;
                        else {
                            *code++ = OP_UPTO + repeat_type;
                            PUT2INC(code, 0, repeat_max);
                        }
                    }

                    /* A repeat minimum of 1 is optimized into some special
                    cases. If the maximum is unlimited, we use OP_PLUS.
                    Otherwise, the original item is left in place and, if the
                    maximum is greater than 1, we use OP_UPTO with one less than
                    the maximum. */

                    else if (repeat_min == 1) {
                        if (repeat_max == -1)
                            *code++ = OP_PLUS + repeat_type;
                        else {
                            code = oldcode; /* leave previous item in place */
                            if (repeat_max == 1)
                                goto END_REPEAT;
                            *code++ = OP_UPTO + repeat_type;
                            PUT2INC(code, 0, repeat_max - 1);
                        }
                    }

                    /* The case {n,n} is just an EXACT, while the general case
                    {n,m} is handled as an EXACT followed by an UPTO. */

                    else {
                        *code++ =
                            OP_EXACT +
                            op_type; /* NB EXACT doesn't have repeat_type */
                        PUT2INC(code, 0, repeat_min);

                        /* If the maximum is unlimited, insert an OP_STAR.
                        Before doing so, we have to insert the character for the
                        previous code. For a repeated Unicode property match,
                        there are two extra bytes that define the required
                        property. In UTF-8 mode, long characters have their
                        length in c, with the 0x80 bit as a flag. */

                        if (repeat_max < 0) {
#ifdef SUPPORT_UTF8
                            if (utf8 && c >= 128) {
                                memcpy(code, utf8_char, c & 7);
                                code += c & 7;
                            } else
#endif
                            {
                                *code++ = c;
                                if (prop_type >= 0) {
                                    *code++ = prop_type;
                                    *code++ = prop_value;
                                }
                            }
                            *code++ = OP_STAR + repeat_type;
                        }

                        /* Else insert an UPTO if the max is greater than the
                        min, again preceded by the character, for the previously
                        inserted code. If the UPTO is just for 1 instance, we
                        can use QUERY instead. */

                        else if (repeat_max != repeat_min) {
#ifdef SUPPORT_UTF8
                            if (utf8 && c >= 128) {
                                memcpy(code, utf8_char, c & 7);
                                code += c & 7;
                            } else
#endif
                                *code++ = c;
                            if (prop_type >= 0) {
                                *code++ = prop_type;
                                *code++ = prop_value;
                            }
                            repeat_max -= repeat_min;

                            if (repeat_max == 1) {
                                *code++ = OP_QUERY + repeat_type;
                            } else {
                                *code++ = OP_UPTO + repeat_type;
                                PUT2INC(code, 0, repeat_max);
                            }
                        }
                    }

                    /* The character or character type itself comes last in all
                     * cases. */

#ifdef SUPPORT_UTF8
                    if (utf8 && c >= 128) {
                        memcpy(code, utf8_char, c & 7);
                        code += c & 7;
                    } else
#endif
                        *code++ = c;

                        /* For a repeated Unicode property match, there are two
                        extra bytes that define the required property. */

#ifdef SUPPORT_UCP
                    if (prop_type >= 0) {
                        *code++ = prop_type;
                        *code++ = prop_value;
                    }
#endif
                }

                /* If previous was a character class or a back reference, we put
                the repeat stuff after it, but just skip the item if the repeat
                was {0,0}. */

                else if (*previous == OP_CLASS || *previous == OP_NCLASS ||
#ifdef SUPPORT_UTF8
                         *previous == OP_XCLASS ||
#endif
                         *previous == OP_REF) {
                    if (repeat_max == 0) {
                        code = previous;
                        goto END_REPEAT;
                    }

                    /* All real repeats make it impossible to handle partial
                    matching (maybe one day we will be able to remove this
                    restriction). */

                    if (repeat_max != 1)
                        cd->external_flags |= PCRE_NOPARTIAL;

                    if (repeat_min == 0 && repeat_max == -1)
                        *code++ = OP_CRSTAR + repeat_type;
                    else if (repeat_min == 1 && repeat_max == -1)
                        *code++ = OP_CRPLUS + repeat_type;
                    else if (repeat_min == 0 && repeat_max == 1)
                        *code++ = OP_CRQUERY + repeat_type;
                    else {
                        *code++ = OP_CRRANGE + repeat_type;
                        PUT2INC(code, 0, repeat_min);
                        if (repeat_max == -1)
                            repeat_max = 0; /* 2-byte encoding for max */
                        PUT2INC(code, 0, repeat_max);
                    }
                }

                /* If previous was a bracket group, we may have to replicate it
                in certain cases. */

                else if (*previous == OP_BRA || *previous == OP_CBRA ||
                         *previous == OP_ONCE || *previous == OP_COND) {
                    register int i;
                    int ketoffset = 0;
                    int len = code - previous;
                    uschar* bralink = NULL;

                    /* Repeating a DEFINE group is pointless */

                    if (*previous == OP_COND &&
                        previous[LINK_SIZE + 1] == OP_DEF) {
                        *errorcodeptr = ERR55;
                        goto FAILED;
                    }

                    /* If the maximum repeat count is unlimited, find the end of
                    the bracket by scanning through from the start, and compute
                    the offset back to it from the current code pointer. There
                    may be an OP_OPT setting following the final KET, so we
                    can't find the end just by going back from the code pointer.
                  */

                    if (repeat_max == -1) {
                        register uschar* ket = previous;
                        do
                            ket += GET(ket, 1);
                        while (*ket != OP_KET);
                        ketoffset = code - ket;
                    }

                    /* The case of a zero minimum is special because of the need
                    to stick OP_BRAZERO in front of it, and because the group
                    appears once in the data, whereas in other cases it appears
                    the minimum number of times. For this reason, it is simplest
                    to treat this case separately, as otherwise the code gets
                    far too messy. There are several special subcases when the
                    minimum is zero. */

                    if (repeat_min == 0) {
                        /* If the maximum is also zero, we just omit the group
                        from the output altogether. */

                        if (repeat_max == 0) {
                            code = previous;
                            goto END_REPEAT;
                        }

                        /* If the maximum is 1 or unlimited, we just have to
                        stick in the BRAZERO and do no more at this point.
                        However, we do need to adjust any OP_RECURSE calls
                        inside the group that refer to the group itself or any
                        internal or forward referenced group, because the offset
                        is from the start of the whole regex. Temporarily
                        terminate the pattern while doing this. */

                        if (repeat_max <= 1) {
                            *code = OP_END;
                            adjust_recurse(previous, 1, utf8, cd, save_hwm);
                            memmove(previous + 1, previous, len);
                            code++;
                            *previous++ = OP_BRAZERO + repeat_type;
                        }

                        /* If the maximum is greater than 1 and limited, we have
                        to replicate in a nested fashion, sticking OP_BRAZERO
                        before each set of brackets. The first one has to be
                        handled carefully because it's the original copy, which
                        has to be moved up. The remainder can be handled by code
                        that is common with the non-zero minimum case below. We
                        have to adjust the value or repeat_max, since one less
                        copy is required. Once again, we may have to adjust any
                        OP_RECURSE calls inside the group. */

                        else {
                            int offset;
                            *code = OP_END;
                            adjust_recurse(previous, 2 + LINK_SIZE, utf8, cd,
                                           save_hwm);
                            memmove(previous + 2 + LINK_SIZE, previous, len);
                            code += 2 + LINK_SIZE;
                            *previous++ = OP_BRAZERO + repeat_type;
                            *previous++ = OP_BRA;

                            /* We chain together the bracket offset fields that
                            have to be filled in later when the ends of the
                            brackets are reached. */

                            offset = (bralink == NULL) ? 0 : previous - bralink;
                            bralink = previous;
                            PUTINC(previous, 0, offset);
                        }

                        repeat_max--;
                    }

                    /* If the minimum is greater than zero, replicate the group
                    as many times as necessary, and adjust the maximum to the
                    number of subsequent copies that we need. If we set a first
                    char from the group, and didn't set a required char, copy
                    the latter from the former. If there are any forward
                    reference subroutine calls in the group, there will be
                    entries on the workspace list; replicate these with an
                    appropriate increment. */

                    else {
                        if (repeat_min > 1) {
                            /* In the pre-compile phase, we don't actually do
                            the replication. We just adjust the length as if we
                            had. Do some paranoid checks for potential integer
                            overflow. */

                            if (lengthptr != NULL) {
                                int delta = (repeat_min - 1) * length_prevgroup;
                                if ((pika_float)(repeat_min - 1) *
                                            (pika_float)length_prevgroup >
                                        (pika_float)INT_MAX ||
                                    OFLOW_MAX - *lengthptr < delta) {
                                    *errorcodeptr = ERR20;
                                    goto FAILED;
                                }
                                *lengthptr += delta;
                            }

                            /* This is compiling for real */

                            else {
                                if (groupsetfirstbyte && reqbyte < 0)
                                    reqbyte = firstbyte;
                                for (i = 1; i < repeat_min; i++) {
                                    uschar* hc;
                                    uschar* this_hwm = cd->hwm;
                                    memcpy(code, previous, len);
                                    for (hc = save_hwm; hc < this_hwm;
                                         hc += LINK_SIZE) {
                                        PUT(cd->hwm, 0, GET(hc, 0) + len);
                                        cd->hwm += LINK_SIZE;
                                    }
                                    save_hwm = this_hwm;
                                    code += len;
                                }
                            }
                        }

                        if (repeat_max > 0)
                            repeat_max -= repeat_min;
                    }

                    /* This code is common to both the zero and non-zero minimum
                    cases. If the maximum is limited, it replicates the group in
                    a nested fashion, remembering the bracket starts on a stack.
                    In the case of a zero minimum, the first one was set up
                    above. In all cases the repeat_max now specifies the number
                    of additional copies needed. Again, we must remember to
                    replicate entries on the forward reference list. */

                    if (repeat_max >= 0) {
                        /* In the pre-compile phase, we don't actually do the
                        replication. We just adjust the length as if we had. For
                        each repetition we must add 1 to the length for BRAZERO
                        and for all but the last repetition we must add 2 +
                        2*LINKSIZE to allow for the nesting that occurs. Do some
                        paranoid checks to avoid integer overflow. */

                        if (lengthptr != NULL && repeat_max > 0) {
                            int delta =
                                repeat_max *
                                    (length_prevgroup + 1 + 2 + 2 * LINK_SIZE) -
                                2 - 2 * LINK_SIZE; /* Last one doesn't nest */
                            if ((pika_float)repeat_max *
                                        (pika_float)(length_prevgroup + 1 + 2 +
                                                     2 * LINK_SIZE) >
                                    (pika_float)INT_MAX ||
                                OFLOW_MAX - *lengthptr < delta) {
                                *errorcodeptr = ERR20;
                                goto FAILED;
                            }
                            *lengthptr += delta;
                        }

                        /* This is compiling for real */

                        else
                            for (i = repeat_max - 1; i >= 0; i--) {
                                uschar* hc;
                                uschar* this_hwm = cd->hwm;

                                *code++ = OP_BRAZERO + repeat_type;

                                /* All but the final copy start a new nesting,
                                maintaining the chain of brackets outstanding.
                              */

                                if (i != 0) {
                                    int offset;
                                    *code++ = OP_BRA;
                                    offset =
                                        (bralink == NULL) ? 0 : code - bralink;
                                    bralink = code;
                                    PUTINC(code, 0, offset);
                                }

                                memcpy(code, previous, len);
                                for (hc = save_hwm; hc < this_hwm;
                                     hc += LINK_SIZE) {
                                    PUT(cd->hwm, 0,
                                        GET(hc, 0) + len +
                                            ((i != 0) ? 2 + LINK_SIZE : 1));
                                    cd->hwm += LINK_SIZE;
                                }
                                save_hwm = this_hwm;
                                code += len;
                            }

                        /* Now chain through the pending brackets, and fill in
                        their length fields (which are holding the chain links
                        pro tem). */

                        while (bralink != NULL) {
                            int oldlinkoffset;
                            int offset = code - bralink + 1;
                            uschar* bra = code - offset;
                            oldlinkoffset = GET(bra, 1);
                            bralink = (oldlinkoffset == 0)
                                          ? NULL
                                          : bralink - oldlinkoffset;
                            *code++ = OP_KET;
                            PUTINC(code, 0, offset);
                            PUT(bra, 1, offset);
                        }
                    }

                    /* If the maximum is unlimited, set a repeater in the final
                    copy. We can't just offset backwards from the current code
                    point, because we don't know if there's been an options
                    resetting after the ket. The correct offset was computed
                    above.

                    Then, when we are doing the actual compile phase, check to
                    see whether this group is a non-atomic one that could match
                    an empty string. If so, convert the initial operator to the
                    S form (e.g. OP_BRA -> OP_SBRA) so that runtime checking can
                    be done. [This check is also applied to atomic groups at
                    runtime, but in a different way.] */

                    else {
                        uschar* ketcode = code - ketoffset;
                        uschar* bracode = ketcode - GET(ketcode, 1);
                        *ketcode = OP_KETRMAX + repeat_type;
                        if (lengthptr == NULL && *bracode != OP_ONCE) {
                            uschar* scode = bracode;
                            do {
                                if (could_be_empty_branch(scode, ketcode,
                                                          utf8)) {
                                    *bracode += OP_SBRA - OP_BRA;
                                    break;
                                }
                                scode += GET(scode, 1);
                            } while (*scode == OP_ALT);
                        }
                    }
                }

                /* Else there's some kind of shambles */

                else {
                    *errorcodeptr = ERR11;
                    goto FAILED;
                }

                /* If the character following a repeat is '+', or if certain
                optimization tests above succeeded, possessive_quantifier is
                TRUE. For some of the simpler opcodes, there is an special
                alternative opcode for this. For anything else, we wrap the
                entire repeated item inside OP_ONCE brackets. The '+' notation
                is just syntactic sugar, taken from Sun's Java package, but the
                special opcodes can optimize it a bit. The repeated item starts
                at tempcode, not at previous, which might be the first part of a
                string whose (former) last char we repeated.

                Possessifying an 'exact' quantifier has no effect, so we can
                ignore it. But an 'upto' may follow. We skip over an 'exact'
                item, and then test the length of what remains before
                proceeding. */

                if (possessive_quantifier) {
                    int len;
                    if (*tempcode == OP_EXACT || *tempcode == OP_TYPEEXACT ||
                        *tempcode == OP_NOTEXACT)
                        tempcode += _pcre_OP_lengths[*tempcode] +
                                    ((*tempcode == OP_TYPEEXACT &&
                                      (tempcode[3] == OP_PROP ||
                                       tempcode[3] == OP_NOTPROP))
                                         ? 2
                                         : 0);
                    len = code - tempcode;
                    if (len > 0)
                        switch (*tempcode) {
                            case OP_STAR:
                                *tempcode = OP_POSSTAR;
                                break;
                            case OP_PLUS:
                                *tempcode = OP_POSPLUS;
                                break;
                            case OP_QUERY:
                                *tempcode = OP_POSQUERY;
                                break;
                            case OP_UPTO:
                                *tempcode = OP_POSUPTO;
                                break;

                            case OP_TYPESTAR:
                                *tempcode = OP_TYPEPOSSTAR;
                                break;
                            case OP_TYPEPLUS:
                                *tempcode = OP_TYPEPOSPLUS;
                                break;
                            case OP_TYPEQUERY:
                                *tempcode = OP_TYPEPOSQUERY;
                                break;
                            case OP_TYPEUPTO:
                                *tempcode = OP_TYPEPOSUPTO;
                                break;

                            case OP_NOTSTAR:
                                *tempcode = OP_NOTPOSSTAR;
                                break;
                            case OP_NOTPLUS:
                                *tempcode = OP_NOTPOSPLUS;
                                break;
                            case OP_NOTQUERY:
                                *tempcode = OP_NOTPOSQUERY;
                                break;
                            case OP_NOTUPTO:
                                *tempcode = OP_NOTPOSUPTO;
                                break;

                            default:
                                memmove(tempcode + 1 + LINK_SIZE, tempcode,
                                        len);
                                code += 1 + LINK_SIZE;
                                len += 1 + LINK_SIZE;
                                tempcode[0] = OP_ONCE;
                                *code++ = OP_KET;
                                PUTINC(code, 0, len);
                                PUT(tempcode, 1, len);
                                break;
                        }
                }

                /* In all case we no longer have a previous item. We also set
                the "follows varying string" flag for subsequently encountered
                reqbytes if it isn't already set and we have just passed a
                varying length item. */

            END_REPEAT:
                previous = NULL;
                cd->req_varyopt |= reqvary;
                break;

                /* ===================================================================*/
                /* Start of nested parenthesized sub-expression, or comment or
                lookahead or lookbehind or option setting or condition or all
                the other extended parenthesis forms.  */

            case '(':
                newoptions = options;
                skipbytes = 0;
                bravalue = OP_CBRA;
                save_hwm = cd->hwm;
                reset_bracount = FALSE;

                /* First deal with various "verbs" that can be introduced by
                 * '*'. */

                if (*(++ptr) == '*' &&
                    (cd->ctypes[ptr[1]] & ctype_letter) != 0) {
                    int i, namelen;
                    const char* vn = verbnames;
                    const uschar* name = ++ptr;
                    previous = NULL;
                    while ((cd->ctypes[*++ptr] & ctype_letter) != 0)
                        ;
                    if (*ptr == ':') {
                        *errorcodeptr = ERR59; /* Not supported */
                        goto FAILED;
                    }
                    if (*ptr != ')') {
                        *errorcodeptr = ERR60;
                        goto FAILED;
                    }
                    namelen = ptr - name;
                    for (i = 0; i < verbcount; i++) {
                        if (namelen == verbs[i].len &&
                            strncmp((char*)name, vn, namelen) == 0) {
                            *code = verbs[i].op;
                            if (*code++ == OP_ACCEPT)
                                cd->had_accept = TRUE;
                            break;
                        }
                        vn += verbs[i].len + 1;
                    }
                    if (i < verbcount)
                        continue;
                    *errorcodeptr = ERR60;
                    goto FAILED;
                }

                /* Deal with the extended parentheses; all are introduced by
                '?', and the appearance of any of them means that this is not a
                capturing group. */

                else if (*ptr == '?') {
                    int i, set, unset, namelen;
                    int* optset;
                    const uschar* name;
                    uschar* slot;

                    switch (*(++ptr)) {
                        case '#': /* Comment; skip to ket */
                            ptr++;
                            while (*ptr != 0 && *ptr != ')')
                                ptr++;
                            if (*ptr == 0) {
                                *errorcodeptr = ERR18;
                                goto FAILED;
                            }
                            continue;

                        /* ------------------------------------------------------------
                         */
                        case '|': /* Reset capture count for each branch */
                            reset_bracount = TRUE;
                        /* Fall through */

                        /* ------------------------------------------------------------
                         */
                        case ':': /* Non-capturing bracket */
                            bravalue = OP_BRA;
                            ptr++;
                            break;

                        /* ------------------------------------------------------------
                         */
                        case '(':
                            bravalue = OP_COND; /* Conditional group */

                            /* A condition can be an assertion, a number
                            (referring to a numbered group), a name (referring
                            to a named group), or 'R', referring to recursion.
                            R<digits> and R&name are also permitted for
                            recursion tests.

                            There are several syntaxes for testing a named
                            group: (?(name)) is used by Python; Perl 5.10
                            onwards uses (?(<name>) or (?('name')).

                            There are two unfortunate ambiguities, caused by
                            history. (a) 'R' can be the recursive thing or the
                            name 'R' (and similarly for 'R' followed by digits),
                            and (b) a number could be a name that consists of
                            digits. In both cases, we look for a name first; if
                            not found, we try the other cases. */

                            /* For conditions that are assertions, check the
                            syntax, and then exit the switch. This will take
                            control down to where bracketed groups, including
                            assertions, are processed. */

                            if (ptr[1] == '?' &&
                                (ptr[2] == '=' || ptr[2] == '!' ||
                                 ptr[2] == '<'))
                                break;

                            /* Most other conditions use OP_CREF (a couple
                            change to OP_RREF below), and all need to skip 3
                            bytes at the start of the group. */

                            code[1 + LINK_SIZE] = OP_CREF;
                            skipbytes = 3;
                            refsign = -1;

                            /* Check for a test for recursion in a named group.
                             */

                            if (ptr[1] == 'R' && ptr[2] == '&') {
                                terminator = -1;
                                ptr += 2;
                                code[1 + LINK_SIZE] =
                                    OP_RREF; /* Change the type of test */
                            }

                            /* Check for a test for a named group's having been
                            set, using the Perl syntax (?(<name>) or (?('name')
                          */

                            else if (ptr[1] == '<') {
                                terminator = '>';
                                ptr++;
                            } else if (ptr[1] == '\'') {
                                terminator = '\'';
                                ptr++;
                            } else {
                                terminator = 0;
                                if (ptr[1] == '-' || ptr[1] == '+')
                                    refsign = *(++ptr);
                            }

                            /* We now expect to read a name; any thing else is
                             * an error */

                            if ((cd->ctypes[ptr[1]] & ctype_word) == 0) {
                                ptr += 1; /* To get the right offset */
                                *errorcodeptr = ERR28;
                                goto FAILED;
                            }

                            /* Read the name, but also get it as a number if
                             * it's all digits */

                            recno = 0;
                            name = ++ptr;
                            while ((cd->ctypes[*ptr] & ctype_word) != 0) {
                                if (recno >= 0)
                                    recno = ((digitab[*ptr] & ctype_digit) != 0)
                                                ? recno * 10 + *ptr - '0'
                                                : -1;
                                ptr++;
                            }
                            namelen = ptr - name;

                            if ((terminator > 0 && *ptr++ != terminator) ||
                                *ptr++ != ')') {
                                ptr--; /* Error offset */
                                *errorcodeptr = ERR26;
                                goto FAILED;
                            }

                            /* Do no further checking in the pre-compile phase.
                             */

                            if (lengthptr != NULL)
                                break;

                            /* In the real compile we do the work of looking for
                            the actual reference. If the string started with "+"
                            or "-" we require the rest to be digits, in which
                            case recno will be set. */

                            if (refsign > 0) {
                                if (recno <= 0) {
                                    *errorcodeptr = ERR58;
                                    goto FAILED;
                                }
                                recno = (refsign == '-')
                                            ? cd->bracount - recno + 1
                                            : recno + cd->bracount;
                                if (recno <= 0 || recno > cd->final_bracount) {
                                    *errorcodeptr = ERR15;
                                    goto FAILED;
                                }
                                PUT2(code, 2 + LINK_SIZE, recno);
                                break;
                            }

                            /* Otherwise (did not start with "+" or "-"), start
                            by looking for the name. */

                            slot = cd->name_table;
                            for (i = 0; i < cd->names_found; i++) {
                                if (strncmp((char*)name, (char*)slot + 2,
                                            namelen) == 0)
                                    break;
                                slot += cd->name_entry_size;
                            }

                            /* Found a previous named subpattern */

                            if (i < cd->names_found) {
                                recno = GET2(slot, 0);
                                PUT2(code, 2 + LINK_SIZE, recno);
                            }

                            /* Search the pattern for a forward reference */

                            else if ((i = find_parens(
                                          ptr, cd->bracount, name, namelen,
                                          (options & PCRE_EXTENDED) != 0)) >
                                     0) {
                                PUT2(code, 2 + LINK_SIZE, i);
                            }

                            /* If terminator == 0 it means that the name
                            followed directly after the opening parenthesis
                            [e.g. (?(abc)...] and in this case there are some
                            further alternatives to try. For the cases where
                            terminator != 0 [things like (?(<name>... or
                            (?('name')... or (?(R&name)... ] we have now checked
                            all the possibilities, so give an error. */

                            else if (terminator != 0) {
                                *errorcodeptr = ERR15;
                                goto FAILED;
                            }

                            /* Check for (?(R) for recursion. Allow digits after
                            R to specify a specific group number. */

                            else if (*name == 'R') {
                                recno = 0;
                                for (i = 1; i < namelen; i++) {
                                    if ((digitab[name[i]] & ctype_digit) == 0) {
                                        *errorcodeptr = ERR15;
                                        goto FAILED;
                                    }
                                    recno = recno * 10 + name[i] - '0';
                                }
                                if (recno == 0)
                                    recno = RREF_ANY;
                                code[1 + LINK_SIZE] =
                                    OP_RREF; /* Change test type */
                                PUT2(code, 2 + LINK_SIZE, recno);
                            }

                            /* Similarly, check for the (?(DEFINE) "condition",
                            which is always false. */

                            else if (namelen == 6 &&
                                     strncmp((char*)name, "DEFINE", 6) == 0) {
                                code[1 + LINK_SIZE] = OP_DEF;
                                skipbytes = 1;
                            }

                            /* Check for the "name" actually being a subpattern
                            number. We are in the second pass here, so
                            final_bracount is set. */

                            else if (recno > 0 && recno <= cd->final_bracount) {
                                PUT2(code, 2 + LINK_SIZE, recno);
                            }

                            /* Either an unidentified subpattern, or a reference
                               to (?(0) */

                            else {
                                *errorcodeptr = (recno == 0) ? ERR35 : ERR15;
                                goto FAILED;
                            }
                            break;

                        /* ------------------------------------------------------------
                         */
                        case '=': /* Positive lookahead */
                            bravalue = OP_ASSERT;
                            ptr++;
                            break;

                        /* ------------------------------------------------------------
                         */
                        case '!': /* Negative lookahead */
                            ptr++;
                            if (*ptr == ')') /* Optimize (?!) */
                            {
                                *code++ = OP_FAIL;
                                previous = NULL;
                                continue;
                            }
                            bravalue = OP_ASSERT_NOT;
                            break;

                        /* ------------------------------------------------------------
                         */
                        case '<': /* Lookbehind or named define */
                            switch (ptr[1]) {
                                case '=': /* Positive lookbehind */
                                    bravalue = OP_ASSERTBACK;
                                    ptr += 2;
                                    break;

                                case '!': /* Negative lookbehind */
                                    bravalue = OP_ASSERTBACK_NOT;
                                    ptr += 2;
                                    break;

                                default: /* Could be name define, else bad */
                                    if ((cd->ctypes[ptr[1]] & ctype_word) != 0)
                                        goto DEFINE_NAME;
                                    ptr++; /* Correct offset for error */
                                    *errorcodeptr = ERR24;
                                    goto FAILED;
                            }
                            break;

                        /* ------------------------------------------------------------
                         */
                        case '>': /* One-time brackets */
                            bravalue = OP_ONCE;
                            ptr++;
                            break;

                        /* ------------------------------------------------------------
                         */
                        case 'C': /* Callout - may be followed by digits; */
                            previous_callout =
                                code; /* Save for later completion */
                            after_manual_callout =
                                1; /* Skip one item before completing */
                            *code++ = OP_CALLOUT;
                            {
                                int n = 0;
                                while ((digitab[*(++ptr)] & ctype_digit) != 0)
                                    n = n * 10 + *ptr - '0';
                                if (*ptr != ')') {
                                    *errorcodeptr = ERR39;
                                    goto FAILED;
                                }
                                if (n > 255) {
                                    *errorcodeptr = ERR38;
                                    goto FAILED;
                                }
                                *code++ = n;
                                PUT(code, 0,
                                    ptr - cd->start_pattern +
                                        1);              /* Pattern offset */
                                PUT(code, LINK_SIZE, 0); /* Default length */
                                code += 2 * LINK_SIZE;
                            }
                            previous = NULL;
                            continue;

                        /* ------------------------------------------------------------
                         */
                        case 'P': /* Python-style named subpattern handling */
                            if (*(++ptr) == '=' ||
                                *ptr == '>') /* Reference or recursion */
                            {
                                is_recurse = *ptr == '>';
                                terminator = ')';
                                goto NAMED_REF_OR_RECURSE;
                            } else if (*ptr != '<') /* Test for Python-style
                                                       definition */
                            {
                                *errorcodeptr = ERR41;
                                goto FAILED;
                            }
                        /* Fall through to handle (?P< as (?< is handled */

                        /* ------------------------------------------------------------
                         */
                        DEFINE_NAME: /* Come here from (?< handling */
                        case '\'': {
                            terminator = (*ptr == '<') ? '>' : '\'';
                            name = ++ptr;

                            while ((cd->ctypes[*ptr] & ctype_word) != 0)
                                ptr++;
                            namelen = ptr - name;

                            /* In the pre-compile phase, just do a syntax check.
                             */

                            if (lengthptr != NULL) {
                                if (*ptr != terminator) {
                                    *errorcodeptr = ERR42;
                                    goto FAILED;
                                }
                                if (cd->names_found >= MAX_NAME_COUNT) {
                                    *errorcodeptr = ERR49;
                                    goto FAILED;
                                }
                                if (namelen + 3 > cd->name_entry_size) {
                                    cd->name_entry_size = namelen + 3;
                                    if (namelen > MAX_NAME_SIZE) {
                                        *errorcodeptr = ERR48;
                                        goto FAILED;
                                    }
                                }
                            }

                            /* In the real compile, create the entry in the
                               table */

                            else {
                                slot = cd->name_table;
                                for (i = 0; i < cd->names_found; i++) {
                                    int crc = memcmp(name, slot + 2, namelen);
                                    if (crc == 0) {
                                        if (slot[2 + namelen] == 0) {
                                            if ((options & PCRE_DUPNAMES) ==
                                                0) {
                                                *errorcodeptr = ERR43;
                                                goto FAILED;
                                            }
                                        } else
                                            crc = -1; /* Current name is
                                                         substring */
                                    }
                                    if (crc < 0) {
                                        memmove(slot + cd->name_entry_size,
                                                slot,
                                                (cd->names_found - i) *
                                                    cd->name_entry_size);
                                        break;
                                    }
                                    slot += cd->name_entry_size;
                                }

                                PUT2(slot, 0, cd->bracount + 1);
                                memcpy(slot + 2, name, namelen);
                                slot[2 + namelen] = 0;
                            }
                        }

                            /* In both cases, count the number of names we've
                             * encountered. */

                            ptr++; /* Move past > or ' */
                            cd->names_found++;
                            goto NUMBERED_GROUP;

                        /* ------------------------------------------------------------
                         */
                        case '&': /* Perl recursion/subroutine syntax */
                            terminator = ')';
                            is_recurse = TRUE;
                            /* Fall through */

                            /* We come here from the Python syntax above that
                            handles both references (?P=name) and recursion
                            (?P>name), as well as falling through from the Perl
                            recursion syntax (?&name). We also come here from
                            the Perl \k<name> or \k'name' back reference syntax
                            and the \k{name} .NET syntax. */

                        NAMED_REF_OR_RECURSE:
                            name = ++ptr;
                            while ((cd->ctypes[*ptr] & ctype_word) != 0)
                                ptr++;
                            namelen = ptr - name;

                            /* In the pre-compile phase, do a syntax check and
                            set a dummy reference number. */

                            if (lengthptr != NULL) {
                                if (namelen == 0) {
                                    *errorcodeptr = ERR62;
                                    goto FAILED;
                                }
                                if (*ptr != terminator) {
                                    *errorcodeptr = ERR42;
                                    goto FAILED;
                                }
                                if (namelen > MAX_NAME_SIZE) {
                                    *errorcodeptr = ERR48;
                                    goto FAILED;
                                }
                                recno = 0;
                            }

                            /* In the real compile, seek the name in the table.
                            We check the name first, and then check that we have
                            reached the end of the name in the table. That way,
                            if the name that is longer than any in the table,
                            the comparison will fail without reading beyond the
                            table entry. */

                            else {
                                slot = cd->name_table;
                                for (i = 0; i < cd->names_found; i++) {
                                    if (strncmp((char*)name, (char*)slot + 2,
                                                namelen) == 0 &&
                                        slot[2 + namelen] == 0)
                                        break;
                                    slot += cd->name_entry_size;
                                }

                                if (i < cd->names_found) /* Back reference */
                                {
                                    recno = GET2(slot, 0);
                                } else if ((recno = /* Forward back reference */
                                            find_parens(
                                                ptr, cd->bracount, name,
                                                namelen,
                                                (options & PCRE_EXTENDED) !=
                                                    0)) <= 0) {
                                    *errorcodeptr = ERR15;
                                    goto FAILED;
                                }
                            }

                            /* In both phases, we can now go to the code than
                            handles numerical recursion or backreferences. */

                            if (is_recurse)
                                goto HANDLE_RECURSION;
                            else
                                goto HANDLE_REFERENCE;

                        /* ------------------------------------------------------------
                         */
                        case 'R':  /* Recursion */
                            ptr++; /* Same as (?0)      */
                        /* Fall through */

                        /* ------------------------------------------------------------
                         */
                        case '-':
                        case '+':
                        case '0':
                        case '1':
                        case '2':
                        case '3':
                        case '4': /* Recursion or */
                        case '5':
                        case '6':
                        case '7':
                        case '8':
                        case '9': /* subroutine */
                        {
                            const uschar* called;

                            if ((refsign = *ptr) == '+') {
                                ptr++;
                                if ((digitab[*ptr] & ctype_digit) == 0) {
                                    *errorcodeptr = ERR63;
                                    goto FAILED;
                                }
                            } else if (refsign == '-') {
                                if ((digitab[ptr[1]] & ctype_digit) == 0)
                                    goto OTHER_CHAR_AFTER_QUERY;
                                ptr++;
                            }

                            recno = 0;
                            while ((digitab[*ptr] & ctype_digit) != 0)
                                recno = recno * 10 + *ptr++ - '0';

                            if (*ptr != ')') {
                                *errorcodeptr = ERR29;
                                goto FAILED;
                            }

                            if (refsign == '-') {
                                if (recno == 0) {
                                    *errorcodeptr = ERR58;
                                    goto FAILED;
                                }
                                recno = cd->bracount - recno + 1;
                                if (recno <= 0) {
                                    *errorcodeptr = ERR15;
                                    goto FAILED;
                                }
                            } else if (refsign == '+') {
                                if (recno == 0) {
                                    *errorcodeptr = ERR58;
                                    goto FAILED;
                                }
                                recno += cd->bracount;
                            }

                            /* Come here from code above that handles a named
                             * recursion */

                        HANDLE_RECURSION:

                            previous = code;
                            called = cd->start_code;

                            /* When we are actually compiling, find the bracket
                            that is being referenced. Temporarily end the regex
                            in case it doesn't exist before this point. If we
                            end up with a forward reference, first check that
                            the bracket does occur later so we can give the
                            error (and position) now. Then remember this forward
                            reference in the workspace so it can be filled in at
                            the end. */

                            if (lengthptr == NULL) {
                                *code = OP_END;
                                if (recno != 0)
                                    called = find_bracket(cd->start_code, utf8,
                                                          recno);

                                /* Forward reference */

                                if (called == NULL) {
                                    if (find_parens(
                                            ptr, cd->bracount, NULL, recno,
                                            (options & PCRE_EXTENDED) != 0) <
                                        0) {
                                        *errorcodeptr = ERR15;
                                        goto FAILED;
                                    }
                                    called = cd->start_code + recno;
                                    PUTINC(
                                        cd->hwm, 0,
                                        code + 2 + LINK_SIZE - cd->start_code);
                                }

                                /* If not a forward reference, and the
                                subpattern is still open, this is a recursive
                                call. We check to see if this is a left
                                recursion that could loop for ever, and diagnose
                                that case. */

                                else if (GET(called, 1) == 0 &&
                                         could_be_empty(called, code, bcptr,
                                                        utf8)) {
                                    *errorcodeptr = ERR40;
                                    goto FAILED;
                                }
                            }

                            /* Insert the recursion/subroutine item,
                            automatically wrapped inside "once" brackets. Set up
                            a "previous group" length so that a subsequent
                            quantifier will work. */

                            *code = OP_ONCE;
                            PUT(code, 1, 2 + 2 * LINK_SIZE);
                            code += 1 + LINK_SIZE;

                            *code = OP_RECURSE;
                            PUT(code, 1, called - cd->start_code);
                            code += 1 + LINK_SIZE;

                            *code = OP_KET;
                            PUT(code, 1, 2 + 2 * LINK_SIZE);
                            code += 1 + LINK_SIZE;

                            length_prevgroup = 3 + 3 * LINK_SIZE;
                        }

                            /* Can't determine a first byte now */

                            if (firstbyte == REQ_UNSET)
                                firstbyte = REQ_NONE;
                            continue;

                        /* ------------------------------------------------------------
                         */
                        default: /* Other characters: check option setting */
                        OTHER_CHAR_AFTER_QUERY:
                            set = unset = 0;
                            optset = &set;

                            while (*ptr != ')' && *ptr != ':') {
                                switch (*ptr++) {
                                    case '-':
                                        optset = &unset;
                                        break;

                                    case 'J': /* Record that it changed in the
                                                 external options */
                                        *optset |= PCRE_DUPNAMES;
                                        cd->external_flags |= PCRE_JCHANGED;
                                        break;

                                    case 'i':
                                        *optset |= PCRE_CASELESS;
                                        break;
                                    case 'm':
                                        *optset |= PCRE_MULTILINE;
                                        break;
                                    case 's':
                                        *optset |= PCRE_DOTALL;
                                        break;
                                    case 'x':
                                        *optset |= PCRE_EXTENDED;
                                        break;
                                    case 'U':
                                        *optset |= PCRE_UNGREEDY;
                                        break;
                                    case 'X':
                                        *optset |= PCRE_EXTRA;
                                        break;

                                    default:
                                        *errorcodeptr = ERR12;
                                        ptr--; /* Correct the offset */
                                        goto FAILED;
                                }
                            }

                            /* Set up the changed option bits, but don't change
                             * anything yet. */

                            newoptions = (options | set) & (~unset);

                            /* If the options ended with ')' this is not the
                            start of a nested group with option changes, so the
                            options change at this level. If this item is right
                            at the start of the pattern, the options can be
                            abstracted and made external in the pre-compile
                            phase, and ignored in the compile phase. This can be
                            helpful when matching -- for instance in caseless
                            checking of required bytes.

                            If the code pointer is not (cd->start_code + 1 +
                            LINK_SIZE), we are definitely *not* at the start of
                            the pattern because something has been compiled. In
                            the pre-compile phase, however, the code pointer can
                            have that value after the start, because it gets
                            reset as code is discarded during the pre-compile.
                            However, this can happen only at top level - if we
                            are within parentheses, the starting BRA will still
                            be present. At any parenthesis level, the length
                            value can be used to test if anything has been
                            compiled at that level. Thus, a test for both these
                            conditions is necessary to ensure we correctly
                            detect the start of the pattern in both phases.

                            If we are not at the pattern start, compile code to
                            change the ims options if this setting actually
                            changes any of them. We also pass the new setting
                            back so that it can be put at the start of any
                            following branches, and when this group ends (if we
                            are in a group), a resetting item can be compiled.
                          */

                            if (*ptr == ')') {
                                if (code == cd->start_code + 1 + LINK_SIZE &&
                                    (lengthptr == NULL ||
                                     *lengthptr == 2 + 2 * LINK_SIZE)) {
                                    cd->external_options = newoptions;
                                    options = newoptions;
                                } else {
                                    if ((options & PCRE_IMS) !=
                                        (newoptions & PCRE_IMS)) {
                                        *code++ = OP_OPT;
                                        *code++ = newoptions & PCRE_IMS;
                                    }

                                    /* Change options at this level, and pass
                                    them back for use in subsequent branches.
                                    Reset the greedy defaults and the case value
                                    for firstbyte and reqbyte. */

                                    *optionsptr = options = newoptions;
                                    greedy_default =
                                        ((newoptions & PCRE_UNGREEDY) != 0);
                                    greedy_non_default = greedy_default ^ 1;
                                    req_caseopt =
                                        ((options & PCRE_CASELESS) != 0)
                                            ? REQ_CASELESS
                                            : 0;
                                }

                                previous =
                                    NULL; /* This item can't be repeated */
                                continue; /* It is complete */
                            }

                            /* If the options ended with ':' we are heading into
                            a nested group with possible change of options. Such
                            groups are non-capturing and are not assertions of
                            any kind. All we need to do is skip over the ':';
                            the newoptions value is handled below. */

                            bravalue = OP_BRA;
                            ptr++;
                    } /* End of switch for character following (? */
                }     /* End of (? handling */

                /* Opening parenthesis not followed by '?'. If
                PCRE_NO_AUTO_CAPTURE is set, all unadorned brackets become
                non-capturing and behave like (?:...) brackets. */

                else if ((options & PCRE_NO_AUTO_CAPTURE) != 0) {
                    bravalue = OP_BRA;
                }

                /* Else we have a capturing group. */

                else {
                NUMBERED_GROUP:
                    cd->bracount += 1;
                    PUT2(code, 1 + LINK_SIZE, cd->bracount);
                    skipbytes = 2;
                }

                /* Process nested bracketed regex. Assertions may not be
                repeated, but other kinds can be. All their opcodes are >=
                OP_ONCE. We copy code into a non-register variable in order to
                be able to pass its address because some compilers complain
                otherwise. Pass in a new setting for the ims options if they
                have changed. */

                previous = (bravalue >= OP_ONCE) ? code : NULL;
                *code = bravalue;
                tempcode = code;
                tempreqvary = cd->req_varyopt; /* Save value before bracket */
                length_prevgroup = 0; /* Initialize for pre-compile phase */

                if (!compile_regex(
                        newoptions,         /* The complete new option state */
                        options & PCRE_IMS, /* The previous ims option state */
                        &tempcode,          /* Where to put code (updated) */
                        &ptr,               /* Input pointer (updated) */
                        errorcodeptr,       /* Where to put an error message */
                        (bravalue == OP_ASSERTBACK ||
                         bravalue ==
                             OP_ASSERTBACK_NOT), /* TRUE if back assert */
                        reset_bracount,          /* True if (?| group */
                        skipbytes,               /* Skip over bracket number */
                        &subfirstbyte,           /* For possible first char */
                        &subreqbyte,             /* For possible last char */
                        bcptr,                   /* Current branch chain */
                        cd,                      /* Tables block */
                        (lengthptr == NULL) ? NULL : /* Actual compile phase */
                            &length_prevgroup        /* Pre-compile phase */
                        ))
                    goto FAILED;

                /* At the end of compiling, code is still pointing to the start
                of the group, while tempcode has been updated to point past the
                end of the group and any option resetting that may follow it.
                The pattern pointer (ptr) is on the bracket. */

                /* If this is a conditional bracket, check that there are no
                more than two branches in the group, or just one if it's a
                DEFINE group. We do this in the real compile phase, not in the
                pre-pass, where the whole group may not be available. */

                if (bravalue == OP_COND && lengthptr == NULL) {
                    uschar* tc = code;
                    int condcount = 0;

                    do {
                        condcount++;
                        tc += GET(tc, 1);
                    } while (*tc != OP_KET);

                    /* A DEFINE group is never obeyed inline (the "condition" is
                    always false). It must have only one branch. */

                    if (code[LINK_SIZE + 1] == OP_DEF) {
                        if (condcount > 1) {
                            *errorcodeptr = ERR54;
                            goto FAILED;
                        }
                        bravalue = OP_DEF; /* Just a flag to suppress char
                                              handling below */
                    }

                    /* A "normal" conditional group. If there is just one
                    branch, we must not make use of its firstbyte or reqbyte,
                    because this is equivalent to an empty second branch. */

                    else {
                        if (condcount > 2) {
                            *errorcodeptr = ERR27;
                            goto FAILED;
                        }
                        if (condcount == 1)
                            subfirstbyte = subreqbyte = REQ_NONE;
                    }
                }

                /* Error if hit end of pattern */

                if (*ptr != ')') {
                    *errorcodeptr = ERR14;
                    goto FAILED;
                }

                /* In the pre-compile phase, update the length by the length of
                the group, less the brackets at either end. Then reduce the
                compiled code to just a set of non-capturing brackets so that it
                doesn't use much memory if it is duplicated by a quantifier.*/

                if (lengthptr != NULL) {
                    if (OFLOW_MAX - *lengthptr <
                        length_prevgroup - 2 - 2 * LINK_SIZE) {
                        *errorcodeptr = ERR20;
                        goto FAILED;
                    }
                    *lengthptr += length_prevgroup - 2 - 2 * LINK_SIZE;
                    *code++ = OP_BRA;
                    PUTINC(code, 0, 1 + LINK_SIZE);
                    *code++ = OP_KET;
                    PUTINC(code, 0, 1 + LINK_SIZE);
                    break; /* No need to waste time with special character
                              handling */
                }

                /* Otherwise update the main code pointer to the end of the
                 * group. */

                code = tempcode;

                /* For a DEFINE group, required and first character settings are
                not relevant. */

                if (bravalue == OP_DEF)
                    break;

                /* Handle updating of the required and first characters for
                other types of group. Update for normal brackets of all kinds,
                and conditions with two branches (see code above). If the
                bracket is followed by a quantifier with zero repeat, we have to
                back off. Hence the definition of zeroreqbyte and zerofirstbyte
                outside the main loop so that they can be accessed for the back
                off. */

                zeroreqbyte = reqbyte;
                zerofirstbyte = firstbyte;
                groupsetfirstbyte = FALSE;

                if (bravalue >= OP_ONCE) {
                    /* If we have not yet set a firstbyte in this branch, take
                    it from the subpattern, remembering that it was set here so
                    that a repeat of more than one can replicate it as reqbyte
                    if necessary. If the subpattern has no firstbyte, set "none"
                    for the whole branch. In both cases, a zero repeat forces
                    firstbyte to "none". */

                    if (firstbyte == REQ_UNSET) {
                        if (subfirstbyte >= 0) {
                            firstbyte = subfirstbyte;
                            groupsetfirstbyte = TRUE;
                        } else
                            firstbyte = REQ_NONE;
                        zerofirstbyte = REQ_NONE;
                    }

                    /* If firstbyte was previously set, convert the subpattern's
                    firstbyte into reqbyte if there wasn't one, using the vary
                    flag that was in existence beforehand. */

                    else if (subfirstbyte >= 0 && subreqbyte < 0)
                        subreqbyte = subfirstbyte | tempreqvary;

                    /* If the subpattern set a required byte (or set a first
                    byte that isn't really the first byte - see above), set it.
                  */

                    if (subreqbyte >= 0)
                        reqbyte = subreqbyte;
                }

                /* For a forward assertion, we take the reqbyte, if set. This
                can be helpful if the pattern that follows the assertion doesn't
                set a different char. For example, it's useful for
                /(?=abcde).+/. We can't set firstbyte for an assertion, however
                because it leads to incorrect effect for patterns such as
                /(?=a)a.+/ when the "real" "a" would then become a reqbyte
                instead of a firstbyte. This is overcome by a scan at the end if
                there's no firstbyte, looking for an asserted first char. */

                else if (bravalue == OP_ASSERT && subreqbyte >= 0)
                    reqbyte = subreqbyte;
                break; /* End of processing '(' */

                /* ===================================================================*/
                /* Handle metasequences introduced by \. For ones like \d, the
                ESC_ values are arranged to be the negation of the corresponding
                OP_values. For the back references, the values are ESC_REF plus
                the reference number. Only back references and those types that
                consume a character may be repeated. We can test for values
                between ESC_b and ESC_Z for the latter; this may have to change
                if any new ones are ever created. */

            case '\\':
                tempptr = ptr;
                c = check_escape(&ptr, errorcodeptr, cd->bracount, options,
                                 FALSE);
                if (*errorcodeptr != 0)
                    goto FAILED;

                if (c < 0) {
                    if (-c == ESC_Q) /* Handle start of quoted string */
                    {
                        if (ptr[1] == '\\' && ptr[2] == 'E')
                            ptr += 2; /* avoid empty string */
                        else
                            inescq = TRUE;
                        continue;
                    }

                    if (-c == ESC_E)
                        continue; /* Perl ignores an orphan \E */

                    /* For metasequences that actually match a character, we
                    disable the setting of a first character if it hasn't
                    already been set. */

                    if (firstbyte == REQ_UNSET && -c > ESC_b && -c < ESC_Z)
                        firstbyte = REQ_NONE;

                    /* Set values to reset to if this is followed by a zero
                     * repeat. */

                    zerofirstbyte = firstbyte;
                    zeroreqbyte = reqbyte;

                    /* \k<name> or \k'name' is a back reference by name (Perl
                    syntax). We also support \k{name} (.NET syntax) */

                    if (-c == ESC_k &&
                        (ptr[1] == '<' || ptr[1] == '\'' || ptr[1] == '{')) {
                        is_recurse = FALSE;
                        terminator = (*(++ptr) == '<') ? '>'
                                     : (*ptr == '\'')  ? '\''
                                                       : '}';
                        goto NAMED_REF_OR_RECURSE;
                    }

                    /* Back references are handled specially; must disable
                    firstbyte if not set to cope with cases like (?=(\w+))\1:
                    which would otherwise set
                    ':' later. */

                    if (-c >= ESC_REF) {
                        recno = -c - ESC_REF;

                    HANDLE_REFERENCE
                        : /* Come here from named backref handling */
                        if (firstbyte == REQ_UNSET)
                            firstbyte = REQ_NONE;
                        previous = code;
                        *code++ = OP_REF;
                        PUT2INC(code, 0, recno);
                        cd->backref_map |= (recno < 32) ? (1 << recno) : 1;
                        if (recno > cd->top_backref)
                            cd->top_backref = recno;
                    }
                    /* So are Unicode property matches, if supported. */

#ifdef SUPPORT_UCP
                    else if (-c == ESC_P || -c == ESC_p) {
                        BOOL negated;
                        int pdata;
                        int ptype =
                            get_ucp(&ptr, &negated, &pdata, errorcodeptr);
                        if (ptype < 0)
                            goto FAILED;
                        previous = code;
                        *code++ =
                            ((-c == ESC_p) != negated) ? OP_PROP : OP_NOTPROP;
                        *code++ = ptype;
                        *code++ = pdata;
                    }
#else

                    /* If Unicode properties are not supported, \X, \P, and \p
                    are not allowed. */

                    else if (-c == ESC_X || -c == ESC_P || -c == ESC_p) {
                        *errorcodeptr = ERR45;
                        goto FAILED;
                    }
#endif

                    /* For the rest (including \X when Unicode properties are
                    supported), we can obtain the OP value by negating the
                    escape value. */

                    else {
                        previous = (-c > ESC_b && -c < ESC_Z) ? code : NULL;
                        *code++ = -c;
                    }
                    continue;
                }

                /* We have a data character whose value is in c. In UTF-8 mode
                it may have a value > 127. We set its representation in the
                length/buffer, and then handle it as a data character. */

#ifdef SUPPORT_UTF8
                if (utf8 && c > 127)
                    mclength = _pcre_ord2utf8(c, mcbuffer);
                else
#endif

                {
                    mcbuffer[0] = c;
                    mclength = 1;
                }
                goto ONE_CHAR;

                /* ===================================================================*/
                /* Handle a literal character. It is guaranteed not to be
                whitespace or # when the extended flag is set. If we are in
                UTF-8 mode, it may be a multi-byte literal character. */

            default:
            NORMAL_CHAR:
                mclength = 1;
                mcbuffer[0] = c;

#ifdef SUPPORT_UTF8
                if (utf8 && c >= 0xc0) {
                    while ((ptr[1] & 0xc0) == 0x80)
                        mcbuffer[mclength++] = *(++ptr);
                }
#endif

                /* At this point we have the character's bytes in mcbuffer, and
                the length in mclength. When not in UTF-8 mode, the length is
                always 1. */

            ONE_CHAR:
                previous = code;
                *code++ =
                    ((options & PCRE_CASELESS) != 0) ? OP_CHARNC : OP_CHAR;
                for (c = 0; c < mclength; c++)
                    *code++ = mcbuffer[c];

                /* Remember if \r or \n were seen */

                if (mcbuffer[0] == '\r' || mcbuffer[0] == '\n')
                    cd->external_flags |= PCRE_HASCRORLF;

                /* Set the first and required bytes appropriately. If no
                previous first byte, set it from this character, but revert to
                none on a zero repeat. Otherwise, leave the firstbyte value
                alone, and don't change it on a zero repeat. */

                if (firstbyte == REQ_UNSET) {
                    zerofirstbyte = REQ_NONE;
                    zeroreqbyte = reqbyte;

                    /* If the character is more than one byte long, we can set
                    firstbyte only if it is not to be matched caselessly. */

                    if (mclength == 1 || req_caseopt == 0) {
                        firstbyte = mcbuffer[0] | req_caseopt;
                        if (mclength != 1)
                            reqbyte = code[-1] | cd->req_varyopt;
                    } else
                        firstbyte = reqbyte = REQ_NONE;
                }

                /* firstbyte was previously set; we can set reqbyte only the
                length is 1 or the matching is caseful. */

                else {
                    zerofirstbyte = firstbyte;
                    zeroreqbyte = reqbyte;
                    if (mclength == 1 || req_caseopt == 0)
                        reqbyte = code[-1] | req_caseopt | cd->req_varyopt;
                }

                break; /* End of literal character handling */
        }
    } /* end of big loop */

    /* Control never reaches here by falling through, only by a goto for all the
    error states. Pass back the position in the pattern so that it can be
    displayed to the user for diagnosing the error. */

FAILED:
    *ptrptr = ptr;
    return FALSE;
}

/*************************************************
 *     Compile sequence of alternatives           *
 *************************************************/

/* On entry, ptr is pointing past the bracket character, but on return it
points to the closing bracket, or vertical bar, or end of string. The code
variable is pointing at the byte into which the BRA operator has been stored.
If the ims options are changed at the start (for a (?ims: group) or during any
branch, we need to insert an OP_OPT item at the start of every following branch
to ensure they get set correctly at run time, and also pass the new options
into every subsequent branch compile.

This function is used during the pre-compile phase when we are trying to find
out the amount of memory needed, as well as during the real compile phase. The
value of lengthptr distinguishes the two phases.

Arguments:
  options        option bits, including any changes for this subpattern
  oldims         previous settings of ims option bits
  codeptr        -> the address of the current code pointer
  ptrptr         -> the address of the current pattern pointer
  errorcodeptr   -> pointer to error code variable
  lookbehind     TRUE if this is a lookbehind assertion
  reset_bracount TRUE to reset the count for each branch
  skipbytes      skip this many bytes at start (for brackets and OP_COND)
  firstbyteptr   place to put the first required character, or a negative number
  reqbyteptr     place to put the last required character, or a negative number
  bcptr          pointer to the chain of currently open branches
  cd             points to the data block with tables pointers etc.
  lengthptr      NULL during the real compile phase
                 points to length accumulator during pre-compile phase

Returns:         TRUE on success
*/

static BOOL compile_regex(int options,
                          int oldims,
                          uschar** codeptr,
                          const uschar** ptrptr,
                          int* errorcodeptr,
                          BOOL lookbehind,
                          BOOL reset_bracount,
                          int skipbytes,
                          int* firstbyteptr,
                          int* reqbyteptr,
                          branch_chain* bcptr,
                          compile_data* cd,
                          int* lengthptr) {
    const uschar* ptr = *ptrptr;
    uschar* code = *codeptr;
    uschar* last_branch = code;
    uschar* start_bracket = code;
    uschar* reverse_count = NULL;
    int firstbyte, reqbyte;
    int branchfirstbyte, branchreqbyte;
    int length;
    int orig_bracount;
    int max_bracount;
    branch_chain bc;

    bc.outer = bcptr;
    bc.current = code;

    firstbyte = reqbyte = REQ_UNSET;

    /* Accumulate the length for use in the pre-compile phase. Start with the
    length of the BRA and KET and any extra bytes that are required at the
    beginning. We accumulate in a local variable to save frequent testing of
    lenthptr for NULL. We cannot do this by looking at the value of code at the
    start and end of each alternative, because compiled items are discarded
    during the pre-compile phase so that the work space is not exceeded. */

    length = 2 + 2 * LINK_SIZE + skipbytes;

    /* WARNING: If the above line is changed for any reason, you must also
    change the code that abstracts option settings at the start of the pattern
    and makes them global. It tests the value of length for (2 + 2*LINK_SIZE) in
    the pre-compile phase to find out whether anything has yet been compiled or
    not. */

    /* Offset is set zero to mark that this bracket is still open */

    PUT(code, 1, 0);
    code += 1 + LINK_SIZE + skipbytes;

    /* Loop for each alternative branch */

    orig_bracount = max_bracount = cd->bracount;
    for (;;) {
        /* For a (?| group, reset the capturing bracket count so that each
        branch uses the same numbers. */

        if (reset_bracount)
            cd->bracount = orig_bracount;

        /* Handle a change of ims options at the start of the branch */

        if ((options & PCRE_IMS) != oldims) {
            *code++ = OP_OPT;
            *code++ = options & PCRE_IMS;
            length += 2;
        }

        /* Set up dummy OP_REVERSE if lookbehind assertion */

        if (lookbehind) {
            *code++ = OP_REVERSE;
            reverse_count = code;
            PUTINC(code, 0, 0);
            length += 1 + LINK_SIZE;
        }

        /* Now compile the branch; in the pre-compile phase its length gets
        added into the length. */

        if (!compile_branch(&options, &code, &ptr, errorcodeptr,
                            &branchfirstbyte, &branchreqbyte, &bc, cd,
                            (lengthptr == NULL) ? NULL : &length)) {
            *ptrptr = ptr;
            return FALSE;
        }

        /* Keep the highest bracket count in case (?| was used and some branch
        has fewer than the rest. */

        if (cd->bracount > max_bracount)
            max_bracount = cd->bracount;

        /* In the real compile phase, there is some post-processing to be done.
         */

        if (lengthptr == NULL) {
            /* If this is the first branch, the firstbyte and reqbyte values for
            the branch become the values for the regex. */

            if (*last_branch != OP_ALT) {
                firstbyte = branchfirstbyte;
                reqbyte = branchreqbyte;
            }

            /* If this is not the first branch, the first char and reqbyte have
            to match the values from all the previous branches, except that if
            the previous value for reqbyte didn't have REQ_VARY set, it can
            still match, and we set REQ_VARY for the regex. */

            else {
                /* If we previously had a firstbyte, but it doesn't match the
                new branch, we have to abandon the firstbyte for the regex, but
                if there was previously no reqbyte, it takes on the value of the
                old firstbyte. */

                if (firstbyte >= 0 && firstbyte != branchfirstbyte) {
                    if (reqbyte < 0)
                        reqbyte = firstbyte;
                    firstbyte = REQ_NONE;
                }

                /* If we (now or from before) have no firstbyte, a firstbyte
                from the branch becomes a reqbyte if there isn't a branch
                reqbyte. */

                if (firstbyte < 0 && branchfirstbyte >= 0 && branchreqbyte < 0)
                    branchreqbyte = branchfirstbyte;

                /* Now ensure that the reqbytes match */

                if ((reqbyte & ~REQ_VARY) != (branchreqbyte & ~REQ_VARY))
                    reqbyte = REQ_NONE;
                else
                    reqbyte |= branchreqbyte; /* To "or" REQ_VARY */
            }

            /* If lookbehind, check that this branch matches a fixed-length
            string, and put the length into the OP_REVERSE item. Temporarily
            mark the end of the branch with OP_END. */

            if (lookbehind) {
                int fixed_length;
                *code = OP_END;
                fixed_length = find_fixedlength(last_branch, options);
                DPRINTF(("fixed length = %d\n", fixed_length));
                if (fixed_length < 0) {
                    *errorcodeptr = (fixed_length == -2) ? ERR36 : ERR25;
                    *ptrptr = ptr;
                    return FALSE;
                }
                PUT(reverse_count, 0, fixed_length);
            }
        }

        /* Reached end of expression, either ')' or end of pattern. In the real
        compile phase, go back through the alternative branches and reverse the
        chain of offsets, with the field in the BRA item now becoming an offset
        to the first alternative. If there are no alternatives, it points to the
        end of the group. The length in the terminating ket is always the length
        of the whole bracketed item. If any of the ims options were changed
        inside the group, compile a resetting op-code following, except at the
        very end of the pattern. Return leaving the pointer at the terminating
        char. */

        if (*ptr != '|') {
            if (lengthptr == NULL) {
                int branch_length = code - last_branch;
                do {
                    int prev_length = GET(last_branch, 1);
                    PUT(last_branch, 1, branch_length);
                    branch_length = prev_length;
                    last_branch -= branch_length;
                } while (branch_length > 0);
            }

            /* Fill in the ket */

            *code = OP_KET;
            PUT(code, 1, code - start_bracket);
            code += 1 + LINK_SIZE;

            /* Resetting option if needed */

            if ((options & PCRE_IMS) != oldims && *ptr == ')') {
                *code++ = OP_OPT;
                *code++ = oldims;
                length += 2;
            }

            /* Retain the highest bracket number, in case resetting was used. */

            cd->bracount = max_bracount;

            /* Set values to pass back */

            *codeptr = code;
            *ptrptr = ptr;
            *firstbyteptr = firstbyte;
            *reqbyteptr = reqbyte;
            if (lengthptr != NULL) {
                if (OFLOW_MAX - *lengthptr < length) {
                    *errorcodeptr = ERR20;
                    return FALSE;
                }
                *lengthptr += length;
            }
            return TRUE;
        }

        /* Another branch follows. In the pre-compile phase, we can move the
        code pointer back to where it was for the start of the first branch.
        (That is, pretend that each branch is the only one.)

        In the real compile phase, insert an ALT node. Its length field points
        back to the previous branch while the bracket remains open. At the end
        the chain is reversed. It's done like this so that the start of the
        bracket has a zero offset until it is closed, making it possible to
        detect recursion. */

        if (lengthptr != NULL) {
            code = *codeptr + 1 + LINK_SIZE + skipbytes;
            length += 1 + LINK_SIZE;
        } else {
            *code = OP_ALT;
            PUT(code, 1, code - last_branch);
            bc.current = last_branch = code;
            code += 1 + LINK_SIZE;
        }

        ptr++;
    }
    /* Control never reaches here */
}

/*************************************************
 *          Check for anchored expression         *
 *************************************************/

/* Try to find out if this is an anchored regular expression. Consider each
alternative branch. If they all start with OP_SOD or OP_CIRC, or with a bracket
all of whose alternatives start with OP_SOD or OP_CIRC (recurse ad lib), then
it's anchored. However, if this is a multiline pattern, then only OP_SOD
counts, since OP_CIRC can match in the middle.

We can also consider a regex to be anchored if OP_SOM starts all its branches.
This is the code for \G, which means "match at start of match position, taking
into account the match offset".

A branch is also implicitly anchored if it starts with .* and DOTALL is set,
because that will try the rest of the pattern at all possible matching points,
so there is no point trying again.... er ....

.... except when the .* appears inside capturing parentheses, and there is a
subsequent back reference to those parentheses. We haven't enough information
to catch that case precisely.

At first, the best we could do was to detect when .* was in capturing brackets
and the highest back reference was greater than or equal to that level.
However, by keeping a bitmap of the first 31 back references, we can catch some
of the more common cases more precisely.

Arguments:
  code           points to start of expression (the bracket)
  options        points to the options setting
  bracket_map    a bitmap of which brackets we are inside while testing; this
                  handles up to substring 31; after that we just have to take
                  the less precise approach
  backref_map    the back reference bitmap

Returns:     TRUE or FALSE
*/

static BOOL is_anchored(register const uschar* code,
                        int* options,
                        unsigned int bracket_map,
                        unsigned int backref_map) {
    do {
        const uschar* scode = first_significant_code(
            code + _pcre_OP_lengths[*code], options, PCRE_MULTILINE, FALSE);
        register int op = *scode;

        /* Non-capturing brackets */

        if (op == OP_BRA) {
            if (!is_anchored(scode, options, bracket_map, backref_map))
                return FALSE;
        }

        /* Capturing brackets */

        else if (op == OP_CBRA) {
            int n = GET2(scode, 1 + LINK_SIZE);
            int new_map = bracket_map | ((n < 32) ? (1 << n) : 1);
            if (!is_anchored(scode, options, new_map, backref_map))
                return FALSE;
        }

        /* Other brackets */

        else if (op == OP_ASSERT || op == OP_ONCE || op == OP_COND) {
            if (!is_anchored(scode, options, bracket_map, backref_map))
                return FALSE;
        }

        /* .* is not anchored unless DOTALL is set and it isn't in brackets that
        are or may be referenced. */

        else if ((op == OP_TYPESTAR || op == OP_TYPEMINSTAR ||
                  op == OP_TYPEPOSSTAR) &&
                 (*options & PCRE_DOTALL) != 0) {
            if (scode[1] != OP_ANY || (bracket_map & backref_map) != 0)
                return FALSE;
        }

        /* Check for explicit anchoring */

        else if (op != OP_SOD && op != OP_SOM &&
                 ((*options & PCRE_MULTILINE) != 0 || op != OP_CIRC))
            return FALSE;
        code += GET(code, 1);
    } while (*code == OP_ALT); /* Loop for each alternative */
    return TRUE;
}

/*************************************************
 *         Check for starting with ^ or .*        *
 *************************************************/

/* This is called to find out if every branch starts with ^ or .* so that
"first char" processing can be done to speed things up in multiline
matching and for non-DOTALL patterns that start with .* (which must start at
the beginning or after \n). As in the case of is_anchored() (see above), we
have to take account of back references to capturing brackets that contain .*
because in that case we can't make the assumption.

Arguments:
  code           points to start of expression (the bracket)
  bracket_map    a bitmap of which brackets we are inside while testing; this
                  handles up to substring 31; after that we just have to take
                  the less precise approach
  backref_map    the back reference bitmap

Returns:         TRUE or FALSE
*/

static BOOL is_startline(const uschar* code,
                         unsigned int bracket_map,
                         unsigned int backref_map) {
    do {
        const uschar* scode = first_significant_code(
            code + _pcre_OP_lengths[*code], NULL, 0, FALSE);
        register int op = *scode;

        /* Non-capturing brackets */

        if (op == OP_BRA) {
            if (!is_startline(scode, bracket_map, backref_map))
                return FALSE;
        }

        /* Capturing brackets */

        else if (op == OP_CBRA) {
            int n = GET2(scode, 1 + LINK_SIZE);
            int new_map = bracket_map | ((n < 32) ? (1 << n) : 1);
            if (!is_startline(scode, new_map, backref_map))
                return FALSE;
        }

        /* Other brackets */

        else if (op == OP_ASSERT || op == OP_ONCE || op == OP_COND) {
            if (!is_startline(scode, bracket_map, backref_map))
                return FALSE;
        }

        /* .* means "start at start or after \n" if it isn't in brackets that
        may be referenced. */

        else if (op == OP_TYPESTAR || op == OP_TYPEMINSTAR ||
                 op == OP_TYPEPOSSTAR) {
            if (scode[1] != OP_ANY || (bracket_map & backref_map) != 0)
                return FALSE;
        }

        /* Check for explicit circumflex */

        else if (op != OP_CIRC)
            return FALSE;

        /* Move on to the next alternative */

        code += GET(code, 1);
    } while (*code == OP_ALT); /* Loop for each alternative */
    return TRUE;
}

/*************************************************
 *       Check for asserted fixed first char      *
 *************************************************/

/* During compilation, the "first char" settings from forward assertions are
discarded, because they can cause conflicts with actual literals that follow.
However, if we end up without a first char setting for an unanchored pattern,
it is worth scanning the regex to see if there is an initial asserted first
char. If all branches start with the same asserted char, or with a bracket all
of whose alternatives start with the same asserted char (recurse ad lib), then
we return that char, otherwise -1.

Arguments:
  code       points to start of expression (the bracket)
  options    pointer to the options (used to check casing changes)
  inassert   TRUE if in an assertion

Returns:     -1 or the fixed first char
*/

static int find_firstassertedchar(const uschar* code,
                                  int* options,
                                  BOOL inassert) {
    register int c = -1;
    do {
        int d;
        const uschar* scode = first_significant_code(
            code + 1 + LINK_SIZE, options, PCRE_CASELESS, TRUE);
        register int op = *scode;

        switch (op) {
            default:
                return -1;

            case OP_BRA:
            case OP_CBRA:
            case OP_ASSERT:
            case OP_ONCE:
            case OP_COND:
                if ((d = find_firstassertedchar(scode, options,
                                                op == OP_ASSERT)) < 0)
                    return -1;
                if (c < 0)
                    c = d;
                else if (c != d)
                    return -1;
                break;

            case OP_EXACT: /* Fall through */
                scode += 2;

            case OP_CHAR:
            case OP_CHARNC:
            case OP_PLUS:
            case OP_MINPLUS:
            case OP_POSPLUS:
                if (!inassert)
                    return -1;
                if (c < 0) {
                    c = scode[1];
                    if ((*options & PCRE_CASELESS) != 0)
                        c |= REQ_CASELESS;
                } else if (c != scode[1])
                    return -1;
                break;
        }

        code += GET(code, 1);
    } while (*code == OP_ALT);
    return c;
}

/*************************************************
 *        Compile a Regular Expression            *
 *************************************************/

/* This function takes a string and returns a pointer to a block of store
holding a compiled version of the expression. The original API for this
function had no error code return variable; it is retained for backwards
compatibility. The new function is given a new name.

Arguments:
  pattern       the regular expression
  options       various option bits
  errorcodeptr  pointer to error code variable (pcre_compile2() only)
                  can be NULL if you don't want a code value
  errorptr      pointer to pointer to error text
  erroroffset   ptr offset in pattern where error was detected
  tables        pointer to character tables or NULL

Returns:        pointer to compiled data block, or NULL on error,
                with errorptr and erroroffset set
*/

pcre* pcre_compile(const char* pattern,
                   int options,
                   const char** errorptr,
                   int* erroroffset,
                   const unsigned char* tables) {
    return pcre_compile2(pattern, options, NULL, errorptr, erroroffset, tables);
}

pcre* pcre_compile2(const char* pattern,
                    int options,
                    int* errorcodeptr,
                    const char** errorptr,
                    int* erroroffset,
                    const unsigned char* tables) {
    real_pcre* re;
    int length = 1; /* For final END opcode */
    int firstbyte, reqbyte, newline;
    int errorcode = 0;
    int skipatstart = 0;
#ifdef SUPPORT_UTF8
    BOOL utf8;
#endif
    size_t size;
    uschar* code;
    const uschar* codestart;
    const uschar* ptr;
    compile_data compile_block;
    compile_data* cd = &compile_block;

    /* This space is used for "compiling" into during the first phase, when we
    are computing the amount of memory that is needed. Compiled items are thrown
    away as soon as possible, so that a fairly large buffer should be sufficient
    for this purpose. The same space is used in the second phase for remembering
    where to fill in forward references to subpatterns. */

    uschar cworkspace[COMPILE_WORK_SIZE];

    /* Set this early so that early errors get offset 0. */

    ptr = (const uschar*)pattern;

    /* We can't pass back an error message if errorptr is NULL; I guess the best
    we can do is just return NULL, but we can set a code value if there is a
    code pointer. */

    if (errorptr == NULL) {
        if (errorcodeptr != NULL)
            *errorcodeptr = 99;
        return NULL;
    }

    *errorptr = NULL;
    if (errorcodeptr != NULL)
        *errorcodeptr = ERR0;

    /* However, we can give a message for this error */

    if (erroroffset == NULL) {
        errorcode = ERR16;
        goto PCRE_EARLY_ERROR_RETURN2;
    }

    *erroroffset = 0;

    /* Can't support UTF8 unless PCRE has been compiled to include the code. */

#ifdef SUPPORT_UTF8
    utf8 = (options & PCRE_UTF8) != 0;
    if (utf8 && (options & PCRE_NO_UTF8_CHECK) == 0 &&
        (*erroroffset = _pcre_valid_utf8((uschar*)pattern, -1)) >= 0) {
        errorcode = ERR44;
        goto PCRE_EARLY_ERROR_RETURN2;
    }
#else
    if ((options & PCRE_UTF8) != 0) {
        errorcode = ERR32;
        goto PCRE_EARLY_ERROR_RETURN;
    }
#endif

    if ((options & ~PUBLIC_OPTIONS) != 0) {
        errorcode = ERR17;
        goto PCRE_EARLY_ERROR_RETURN;
    }

    /* Set up pointers to the individual character tables */

    if (tables == NULL)
        tables = _pcre_default_tables;
    cd->lcc = tables + lcc_offset;
    cd->fcc = tables + fcc_offset;
    cd->cbits = tables + cbits_offset;
    cd->ctypes = tables + ctypes_offset;

    /* Check for global one-time settings at the start of the pattern, and
    remember the offset for later. */

    while (ptr[skipatstart] == '(' && ptr[skipatstart + 1] == '*') {
        int newnl = 0;
        int newbsr = 0;

        if (strncmp((char*)(ptr + skipatstart + 2), "CR)", 3) == 0) {
            skipatstart += 5;
            newnl = PCRE_NEWLINE_CR;
        } else if (strncmp((char*)(ptr + skipatstart + 2), "LF)", 3) == 0) {
            skipatstart += 5;
            newnl = PCRE_NEWLINE_LF;
        } else if (strncmp((char*)(ptr + skipatstart + 2), "CRLF)", 5) == 0) {
            skipatstart += 7;
            newnl = PCRE_NEWLINE_CR + PCRE_NEWLINE_LF;
        } else if (strncmp((char*)(ptr + skipatstart + 2), "ANY)", 4) == 0) {
            skipatstart += 6;
            newnl = PCRE_NEWLINE_ANY;
        } else if (strncmp((char*)(ptr + skipatstart + 2), "ANYCRLF)", 8) ==
                   0) {
            skipatstart += 10;
            newnl = PCRE_NEWLINE_ANYCRLF;
        }

        else if (strncmp((char*)(ptr + skipatstart + 2), "BSR_ANYCRLF)", 12) ==
                 0) {
            skipatstart += 14;
            newbsr = PCRE_BSR_ANYCRLF;
        } else if (strncmp((char*)(ptr + skipatstart + 2), "BSR_UNICODE)",
                           12) == 0) {
            skipatstart += 14;
            newbsr = PCRE_BSR_UNICODE;
        }

        if (newnl != 0)
            options = (options & ~PCRE_NEWLINE_BITS) | newnl;
        else if (newbsr != 0)
            options =
                (options & ~(PCRE_BSR_ANYCRLF | PCRE_BSR_UNICODE)) | newbsr;
        else
            break;
    }

    /* Check validity of \R options. */

    switch (options & (PCRE_BSR_ANYCRLF | PCRE_BSR_UNICODE)) {
        case 0:
        case PCRE_BSR_ANYCRLF:
        case PCRE_BSR_UNICODE:
            break;
        default:
            errorcode = ERR56;
            goto PCRE_EARLY_ERROR_RETURN;
    }

    /* Handle different types of newline. The three bits give seven cases. The
    current code allows for fixed one- or two-byte sequences, plus "any" and
    "anycrlf". */

    switch (options & PCRE_NEWLINE_BITS) {
        case 0:
            newline = NEWLINE;
            break; /* Build-time default */
        case PCRE_NEWLINE_CR:
            newline = '\r';
            break;
        case PCRE_NEWLINE_LF:
            newline = '\n';
            break;
        case PCRE_NEWLINE_CR + PCRE_NEWLINE_LF:
            newline = ('\r' << 8) | '\n';
            break;
        case PCRE_NEWLINE_ANY:
            newline = -1;
            break;
        case PCRE_NEWLINE_ANYCRLF:
            newline = -2;
            break;
        default:
            errorcode = ERR56;
            goto PCRE_EARLY_ERROR_RETURN;
    }

    if (newline == -2) {
        cd->nltype = NLTYPE_ANYCRLF;
    } else if (newline < 0) {
        cd->nltype = NLTYPE_ANY;
    } else {
        cd->nltype = NLTYPE_FIXED;
        if (newline > 255) {
            cd->nllen = 2;
            cd->nl[0] = (newline >> 8) & 255;
            cd->nl[1] = newline & 255;
        } else {
            cd->nllen = 1;
            cd->nl[0] = newline;
        }
    }

    /* Maximum back reference and backref bitmap. The bitmap records up to 31
    back references to help in deciding whether (.*) can be treated as anchored
    or not.
    */

    cd->top_backref = 0;
    cd->backref_map = 0;

    /* Reflect pattern for debugging output */

    DPRINTF(
        ("------------------------------------------------------------------"
         "\n"));
    DPRINTF(("%s\n", pattern));

    /* Pretend to compile the pattern while actually just accumulating the
    length of memory required. This behaviour is triggered by passing a non-NULL
    final argument to compile_regex(). We pass a block of workspace (cworkspace)
    for it to compile parts of the pattern into; the compiled code is discarded
    when it is no longer needed, so hopefully this workspace will never
    overflow, though there is a test for its doing so. */

    cd->bracount = cd->final_bracount = 0;
    cd->names_found = 0;
    cd->name_entry_size = 0;
    cd->name_table = NULL;
    cd->start_workspace = cworkspace;
    cd->start_code = cworkspace;
    cd->hwm = cworkspace;
    cd->start_pattern = (const uschar*)pattern;
    cd->end_pattern = (const uschar*)(pattern + strlen(pattern));
    cd->req_varyopt = 0;
    cd->external_options = options;
    cd->external_flags = 0;

    /* Now do the pre-compile. On error, errorcode will be set non-zero, so we
    don't need to look at the result of the function here. The initial options
    have been put into the cd block so that they can be changed if an option
    setting is found within the regex right at the beginning. Bringing initial
    option settings outside can help speed up starting point checks. */

    ptr += skipatstart;
    code = cworkspace;
    *code = OP_BRA;
    (void)compile_regex(cd->external_options, cd->external_options & PCRE_IMS,
                        &code, &ptr, &errorcode, FALSE, FALSE, 0, &firstbyte,
                        &reqbyte, NULL, cd, &length);
    if (errorcode != 0)
        goto PCRE_EARLY_ERROR_RETURN;

    DPRINTF(("end pre-compile: length=%d workspace=%d\n", length,
             cd->hwm - cworkspace));

    if (length > MAX_PATTERN_SIZE) {
        errorcode = ERR20;
        goto PCRE_EARLY_ERROR_RETURN;
    }

    /* Compute the size of data block needed and get it, either from malloc or
    externally provided function. Integer overflow should no longer be possible
    because nowadays we limit the maximum value of cd->names_found and
    cd->name_entry_size. */

    size = length + sizeof(real_pcre) +
           cd->names_found * (cd->name_entry_size + 3);
    re = (real_pcre*)(pcre_malloc)(size);

    if (re == NULL) {
        errorcode = ERR21;
        goto PCRE_EARLY_ERROR_RETURN;
    }

    /* Put in the magic number, and save the sizes, initial options, internal
    flags, and character table pointer. NULL is used for the default character
    tables. The nullpad field is at the end; it's there to help in the case when
    a regex compiled on a system with 4-byte pointers is run on another with
    8-byte pointers. */

    re->magic_number = MAGIC_NUMBER;
    re->size = size;
    re->options = cd->external_options;
    re->flags = cd->external_flags;
    re->dummy1 = 0;
    re->first_byte = 0;
    re->req_byte = 0;
    re->name_table_offset = sizeof(real_pcre);
    re->name_entry_size = cd->name_entry_size;
    re->name_count = cd->names_found;
    re->ref_count = 0;
    re->tables = (tables == _pcre_default_tables) ? NULL : tables;
    re->nullpad = NULL;

    /* The starting points of the name/number translation table and of the code
    are passed around in the compile data block. The start/end pattern and
    initial options are already set from the pre-compile phase, as is the
    name_entry_size field. Reset the bracket count and the names_found field.
    Also reset the hwm field; this time it's used for remembering forward
    references to subpatterns.
    */

    cd->final_bracount =
        cd->bracount; /* Save for checking forward references */
    cd->bracount = 0;
    cd->names_found = 0;
    cd->name_table = (uschar*)re + re->name_table_offset;
    codestart = cd->name_table + re->name_entry_size * re->name_count;
    cd->start_code = codestart;
    cd->hwm = cworkspace;
    cd->req_varyopt = 0;
    cd->had_accept = FALSE;

    /* Set up a starting, non-extracting bracket, then compile the expression.
    On error, errorcode will be set non-zero, so we don't need to look at the
    result of the function here. */

    ptr = (const uschar*)pattern + skipatstart;
    code = (uschar*)codestart;
    *code = OP_BRA;
    (void)compile_regex(re->options, re->options & PCRE_IMS, &code, &ptr,
                        &errorcode, FALSE, FALSE, 0, &firstbyte, &reqbyte, NULL,
                        cd, NULL);
    re->top_bracket = cd->bracount;
    re->top_backref = cd->top_backref;
    re->flags = cd->external_flags;

    if (cd->had_accept)
        reqbyte = -1; /* Must disable after (*ACCEPT) */

    /* If not reached end of pattern on success, there's an excess bracket. */

    if (errorcode == 0 && *ptr != 0)
        errorcode = ERR22;

    /* Fill in the terminating state and check for disastrous overflow, but
    if debugging, leave the test till after things are printed out. */

    *code++ = OP_END;

#ifndef DEBUG
    if (code - codestart > length)
        errorcode = ERR23;
#endif

    /* Fill in any forward references that are required. */

    while (errorcode == 0 && cd->hwm > cworkspace) {
        int offset, recno;
        const uschar* groupptr;
        cd->hwm -= LINK_SIZE;
        offset = GET(cd->hwm, 0);
        recno = GET(codestart, offset);
        groupptr =
            find_bracket(codestart, (re->options & PCRE_UTF8) != 0, recno);
        if (groupptr == NULL)
            errorcode = ERR53;
        else
            PUT(((uschar*)codestart), offset, groupptr - codestart);
    }

    /* Give an error if there's back reference to a non-existent capturing
    subpattern. */

    if (errorcode == 0 && re->top_backref > re->top_bracket)
        errorcode = ERR15;

    /* Failed to compile, or error while post-processing */

    if (errorcode != 0) {
        (pcre_free)(re);
    PCRE_EARLY_ERROR_RETURN:
        *erroroffset = ptr - (const uschar*)pattern;
    PCRE_EARLY_ERROR_RETURN2:
        *errorptr = find_error_text(errorcode);
        if (errorcodeptr != NULL)
            *errorcodeptr = errorcode;
        return NULL;
    }

    /* If the anchored option was not passed, set the flag if we can determine
    that the pattern is anchored by virtue of ^ characters or \A or anything
    else (such as starting with .* when DOTALL is set).

    Otherwise, if we know what the first byte has to be, save it, because that
    speeds up unanchored matches no end. If not, see if we can set the
    PCRE_STARTLINE flag. This is helpful for multiline matches when all branches
    start with ^. and also when all branches start with .* for non-DOTALL
    matches.
    */

    if ((re->options & PCRE_ANCHORED) == 0) {
        int temp_options = re->options; /* May get changed during these scans */
        if (is_anchored(codestart, &temp_options, 0, cd->backref_map))
            re->options |= PCRE_ANCHORED;
        else {
            if (firstbyte < 0)
                firstbyte =
                    find_firstassertedchar(codestart, &temp_options, FALSE);
            if (firstbyte >=
                0) /* Remove caseless flag for non-caseable chars */
            {
                int ch = firstbyte & 255;
                re->first_byte =
                    ((firstbyte & REQ_CASELESS) != 0 && cd->fcc[ch] == ch)
                        ? ch
                        : firstbyte;
                re->flags |= PCRE_FIRSTSET;
            } else if (is_startline(codestart, 0, cd->backref_map))
                re->flags |= PCRE_STARTLINE;
        }
    }

    /* For an anchored pattern, we use the "required byte" only if it follows a
    variable length item in the regex. Remove the caseless flag for non-caseable
    bytes. */

    if (reqbyte >= 0 &&
        ((re->options & PCRE_ANCHORED) == 0 || (reqbyte & REQ_VARY) != 0)) {
        int ch = reqbyte & 255;
        re->req_byte = ((reqbyte & REQ_CASELESS) != 0 && cd->fcc[ch] == ch)
                           ? (reqbyte & ~REQ_CASELESS)
                           : reqbyte;
        re->flags |= PCRE_REQCHSET;
    }

    /* Print out the compiled data if debugging is enabled. This is never the
    case when building a production library. */

#ifdef DEBUG

    printf("Length = %d top_bracket = %d top_backref = %d\n", length,
           re->top_bracket, re->top_backref);

    printf("Options=%08x\n", re->options);

    if ((re->flags & PCRE_FIRSTSET) != 0) {
        int ch = re->first_byte & 255;
        const char* caseless =
            ((re->first_byte & REQ_CASELESS) == 0) ? "" : " (caseless)";
        if (isprint(ch))
            printf("First char = %c%s\n", ch, caseless);
        else
            printf("First char = \\x%02x%s\n", ch, caseless);
    }

    if ((re->flags & PCRE_REQCHSET) != 0) {
        int ch = re->req_byte & 255;
        const char* caseless =
            ((re->req_byte & REQ_CASELESS) == 0) ? "" : " (caseless)";
        if (isprint(ch))
            printf("Req char = %c%s\n", ch, caseless);
        else
            printf("Req char = \\x%02x%s\n", ch, caseless);
    }

    pcre_printint(re, stdout, TRUE);

    /* This check is done here in the debugging case so that the code that
    was compiled can be seen. */

    if (code - codestart > length) {
        (pcre_free)(re);
        *errorptr = find_error_text(ERR23);
        *erroroffset = ptr - (uschar*)pattern;
        if (errorcodeptr != NULL)
            *errorcodeptr = ERR23;
        return NULL;
    }
#endif /* DEBUG */

    return (pcre*)re;
}

/* End of pcre_compile.c */
